Optical composition, cured product, and optical element

ABSTRACT

Provided is a cured product having the following characteristics: the dispersion characteristic and secondary dispersion characteristic of refractive indices are high, the cured product hardy crystallizes, and a chromatic aberration-correcting function is high. The cured product contains at least a structure represented by the general formula (4) and a structure represented by the general formula (5), in which a content of the structure represented by the general formula (5) in the cured product is 0.01 or more and 0.10 or less in terms of a substance amount ratio with respect to the structure represented by the general formula (4).

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an optical composition, a curedproduct, and an optical element, and more particularly, to an opticalcomposition using a (meth)acrylate compound, which has specific opticalcharacteristics, a cured product, and an optical element.

Description of the Related Art

In general, the refractive index of an optical material formed of aglass material, an organic resin, or the like gradually increases as thewavelength of light to be refracted by the material becomes shorter.Indicators each representing the wavelength dispersibility of therefractive index are, for example, an Abbe number (dispersioncharacteristic) (ν_(d)) and a secondary dispersion characteristic(θg,F). The Abbe number and the θg,F value are values peculiar to eachoptical material, but in many cases, the values each fall within acertain range. FIG. 1 is a graph for showing a relationship between thesecondary dispersion characteristic and Abbe number of each ofconventional optical materials (a glass material and an organicmaterial).

The Abbe number (v_(d)) and the secondary dispersion characteristic(θg,F) are represented by the following equations:

Abbe number [ν_(d)]=(n _(d)−1)/(n _(F) −n _(c))

Secondary dispersion characteristic [θg,F]=(n _(g) −n _(F))/(n _(F) −n_(c))

where n_(d) represents a refractive index at a wavelength of 587.6 nm,n_(F) represents a refractive index at a wavelength of 486.1 nm, n_(C)represents a refractive index at a wavelength of 656.3 nm, and n_(g)represents a refractive index at a wavelength of 435.8 nm.

Accordingly, in a refracting optical system, a chromatic aberration canbe reduced by appropriately combining glass materials having differentdispersion characteristics. In, for example, the objective lens of atelescope or the like, a chromatic aberration appearing on its opticalaxis is corrected by using the following materials in combination: aglass material having small dispersion is used as a positive lens, and aglass material having large dispersion is used as a negative lens.However, for example, when the constructions and number of lenses arelimited, or when glass materials to be used are limited, it may becomeextremely difficult to sufficiently correct the chromatic aberration.One method of solving such problem is a method involving exploiting aglass material having an abnormal dispersion characteristic, and thedesign of optical elements involving utilizing the method has beenperformed.

In addition, when an optical element that is excellent in chromaticaberration-correcting function and has, for example, an aspherical shapeas its shape is produced, a method involving, for example, molding anorganic material on a glass material, such as a spherical glass, has thefollowing advantage over a method involving using only a glass materialas a material: an optical element excellent in mass productivity,moldability, degree of freedom in shape, and lightweight property can beproduced. However, the optical characteristic of a conventional organicmaterial falls within a certain limited range (its secondary dispersioncharacteristic [θg,F] is 0.700 or less) as shown in FIG. 1, and hencethe number of organic materials showing specific dispersioncharacteristics is extremely small.

Further, most of the organic materials showing specific dispersioncharacteristics are each a molecule having the following features: aconjugated structure is built by a double bond, a benzene ring, or thelike, and the molecule has high rigidity or a high orientation propertyand is hence liable to crystallize. Accordingly, when any one of theorganic materials showing specific dispersion characteristics is used asan optical composition having added thereto various additives, anonuniform portion may occur in the composition owing to thecrystallization of the organic material.

In such background as described above, in Japanese Patent ApplicationLaid-Open No. 2012-167019, there is a proposal that a specific sulfone(meth)acrylate have a higher secondary dispersion characteristic (higherθg,F characteristic) than that of a general-purpose organic material.

In addition, in Japanese Patent Application Laid-Open No. 2014-43565,there is a proposal that a branched chain substituent be introduced intothe same molecular skeleton as that of Japanese Patent ApplicationLaid-Open No. 2012-167019 for reducing a birefringent index.

SUMMARY OF THE INVENTION

Although the organic material disclosed in Japanese Patent ApplicationLaid-Open No. 2012-167019 has a high θg,F value, owing to its molecularstructure, the material is liable to be oriented and is hence liable tobe a crystal. In addition, the material disclosed in Japanese PatentApplication Laid-Open No. 2014-43565 also has a high θg,F value.However, the material has the same molecular skeleton as that of theorganic material disclosed in Japanese Patent Application Laid-Open No.2012-167019, and hence the material is liable to be a crystal despitethe fact that the material has a branched structure on a side chainthereof.

The present invention has been made in view of the above-mentionedbackground art, and provides an optical composition having the followingfeatures and a cured product obtained by polymerizing the composition,and an optical element using the cured product: the dispersioncharacteristic (Abbe number (ν_(d))) and secondary dispersioncharacteristic (θg,F) of refractive indices fall within an area usefulfor optical design (an area B in FIG. 1), and a period forcrystallization can be made longer than those of the organic materialsdisclosed in Japanese Patent Application Laid-Open No. 2012-167019 andJapanese Patent Application Laid-Open No. 2014-43565.

An optical composition that solves the problems is an opticalcomposition containing at least a compound represented by the generalformula (1) and a compound represented by the general formula (2), inwhich a content of the compound represented by the general formula (2)in the optical composition is 1.0 mass % or more and 10.0 mass % or lesswith respect to the compound represented by the general formula (1):

in the general formula (1) and the general formula (2):

X₁, X₂, Y₁, and Y₂ each represent O or S, and may be identical to ordifferent from one another;

R₁ to R₄ each represent one selected from the group consisting of amethyl group, an ethyl group, a propyl group, an isopropyl group, anallyl group, a 2-(meth)acryloyloxyethyl group, a3-(meth)acryloyloxypropyl group, and a 4-(meth)acryloyloxybutyl group,and may be identical to or different from one another;

Z₁, Z₄, and Z₆ each represent a structure represented by the generalformula (3);

Z₂, Z₃, Z₅, and Z₇ each represent one selected from the group consistingof a hydrogen atom, a methyl group, an ethyl group, an isopropyl group,a methoxy group, an ethoxy group, an isopropoxy group, a methylthiogroup, an ethylthio group, a propylthio group, a2-(meth)acryloyloxyethoxy group, a 3-(meth)acryloyloxypropoxy group, a4-(meth)acryloyloxybutoxy group, and a structure represented by thegeneral formula (3), and may be identical to or different from oneanother; and

Z₈ represents V in a structure represented by the general formula (3);

in the general formula (3), m represents 0 or 1, W represents a hydrogenatom or a methyl group, and V is selected from the group consisting ofthe following substituents:

*—O—**; —S—**;

*—C_13 C_(n)H_(2n)—O—**;*—S—C_(n)H_(2n)—O—**;*—O—C_(n)H_(2n)—S—**; and*—S—C_(n)H_(2n)—S—**;in each of the Z₁ to the Z₇, * of the structure represents a bondinghand with an alkylene moiety and ** thereof represents a bonding handwith a (meth)acryloyl group, in the Z₈, the V does not represent *—O—**and *—S—**, and both of * and ** each represent a bonding hand with analkylene moiety, and a structure represented by C_(n)H_(2n) in the V mayhave a substituent on a carbon atom, and n represents an integerselected from the group consisting of 2 to 5.

A cured product that solves the problems is a cured product, which isobtained by polymerizing the optical composition, the cured productcontaining at least a structure represented by the general formula (4)and a structure represented by the general formula (5), in which acontent of the structure represented by the general formula (5) in thecured product is 0.01 or more and 0.10 or less in terms of a substanceamount ratio with respect to the structure represented by the generalformula (4):

in the general formula (4) and the general formula (5):

X₁, X₂, Y₁, and Y₂ each represent O or S, and may be identical to ordifferent from one another;

R₁ to R₄ each represent one selected from the group consisting of amethyl group, an ethyl group, a propyl group, an isopropyl group, anallyl group, a 2-(meth)acryloyloxyethyl group, a3-(meth)acryloyloxypropyl group, and a 4-(meth)acryloyloxybutyl group,and may be identical to or different from one another;

when the R₁ to the R₄ each represent an allyl group, a2-(meth)acryloyloxyethyl group, a 3-(meth)acryloyloxypropyl group, or a4-(meth)acryloyloxybutyl group, the R₁ to the R₄ may each represent agroup having a bond formed with a cleaved double bond of the allylgroup, the 2-(meth)acryloyloxyethyl group, the 3-(meth)acryloyloxypropylgroup, or the 4-(meth)acryloyloxybutyl group;

Z₁, Z₄, and Z₆ may each represent a structure represented by the generalformula (3) or a structure having a bond formed with a cleaved doublebond of a structure represented by the general formula (3);

Z₂, Z₃, Z₅, and Z₇ each represent one selected from the group consistingof a hydrogen atom, a methyl group, an ethyl group, an isopropyl group,a methoxy group, an ethoxy group, an isopropoxy group, a methylthiogroup, an ethylthio group, a propylthio group, a2-(meth)acryloyloxyethoxy group, a 3-(meth)acryloyloxypropoxy group, a4-(meth)acryloyloxybutoxy group, and a structure represented by thegeneral formula (3), and may be identical to or different from oneanother;

when the Z₂, the Z₃, the Z₅, and the Z₇ each represent a2-(meth)acryloyloxyethoxy group, a 3-(meth)acryloyloxypropoxy group, a4-(meth)acryloyloxybutoxy group, or a structure represented by thegeneral formula (3), the Z₂, the Z₃, the Z₅, and the Z₇ may eachrepresent a structure having a bond formed with a cleaved double bond ofthe 2-(meth)acryloyloxyethoxy group, the 3-(meth)acryloyloxypropoxygroup, the 4-(meth)acryloyloxybutoxy group, or the structure representedby the general formula (3);

at least two broken lines in the general formula (4) or the generalformula (5) each represent the bond formed with the cleaved double bond;and

Z₈ represents V in a structure represented by the general formula (3);

in the general formula (3), m represents 0 or 1, W represents a hydrogenatom or a methyl group, and V is selected from the group consisting ofthe following structures:

*—O—**; *—S—**;

—O—C_(n)H_(2n)—O—**;*—S—C_(n)H_(2n)—O—**;*—O—C_(n)H_(2n)—S—**; and*—S—C_(n)H_(2n)—S—**;in each of the Z₁ to the Z₇, * of the structure represents a bondinghand with an alkylene moiety and ** of the structure represents abonding hand with a (meth)acryloyl group, in the Z₈, the V does notrepresent *—O—** and *—S—**, and both of * and ** each represent abonding hand with an alkylene moiety, and a structure represented byC_(n)H_(2n) in the V may have a substituent on a carbon atom, and nrepresents an integer selected from the group consisting of 2 to 5.

An optical element that solves the problems is an optical elementobtained by molding the cured product.

According to the present invention, the optical composition having thefollowing features and the cured product obtained by polymerizing theoptical composition, and the optical element using the cured product canbe provided: the dispersion characteristic (Abbe number (ν_(d))) andsecondary dispersion characteristic (θg,F) of refractive indices arehigh, and the crystallization of an organic material can be suppressedto an extent larger than that in the related art. In addition, adifference in refractive index characteristic between a cured product ofan optical composition that does not use the present invention and thecured product of the optical composition of the present invention issufficiently small in terms of optical design. Accordingly, according tothe optical composition of the present invention that can suppress theoccurrence of a nonuniform portion occurring at the time ofcrystallization, its storage stability can be improved without anychange in terms of optical design.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph for showing a relationship between the secondarydispersion characteristic and Abbe number of a conventional opticalmaterial.

FIG. 2A and FIG. 2B are each a schematic view for illustrating anexample of an optical element of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

The present invention is described in detail below.

First, an optical composition of the present invention is described.

An optical composition of the present invention includes at least acompound represented by the general formula (1) and a compoundrepresented by the general formula (2), in which a content of thecompound represented by the general formula (2) in the opticalcomposition is 1.0 mass % or more and 10.0 mass % or less with respectto the compound represented by the general formula (1).

In the compound represented by the general formula (1) and the compoundrepresented by the general formula (2), as long as X₁, X₂, Y₁, and Y₂each represent an electron-donating element, the X₁, the X₂, the Y₁, andthe Y₂ are not particularly limited because the dispersioncharacteristic and secondary dispersion characteristic of the opticalcomposition become characteristics within an area where an effect interms of optical design is obtained. However, in consideration of, forexample, the environmental durability and ease of synthesis of each ofthe compounds, the X₁, the X₂, the Y₁, and the Y₂ each represent anoxygen atom (O) or a sulfur atom (S), and may be identical to ordifferent from one another; provided that it is preferred that the X₁and the X₂ be identical to each other, and the Y₁ and the Y₂ beidentical to each other in consideration of the ease of synthesis ofeach of the compounds and the ease with which the compound representedby the general formula (2) is incorporated at 1.0 mass % or more and10.0 mass % or less into the compound represented by the general formula(1). It is more preferred that the X₁, the X₂, the Y₁, and the Y₂ eachrepresent O.

In the compound represented by the general formula (1) and the compoundrepresented by the general formula (2), substituents represented by R₁to R₄ are not particularly limited as long as the substituents can bestably bonded to the X₁, the X₂, the Y₁, and the Y₂, respectively. Atomsto be bonded to the X₁, the X₂, the Y₁, and the Y₂ are preferably carbonatoms. As the molecular weights of the substituents represented by theR₁ to the R₄ increase, the dispersion characteristic and secondarydispersion characteristic of the optical composition reduce.Accordingly, the molecular weights of the substituents are preferablyless than 170. Specific examples of the substituents represented by theR₁ to the R₄ may include, but not limited to, a methyl group, an ethylgroup, a propyl group, an isopropyl group, a tert-butyl group, anisobutyl group, a chloromethyl group, a bromomethyl group, adichloromethyl group, a trichloromethyl group, a fluoromethyl group, adifluoromethyl group, a trifluoromethyl group, a pentyl group, an allylgroup, a 2-(meth)acryloyloxyethyl group, a 3-(meth)acryloyloxypropylgroup, and a 4-(meth)acryloyloxybutyl group. Of those, a methyl group,an ethyl group, a propyl group, an isopropyl group, an allyl group, a2-(meth)acryloyloxyethyl group, a 3-(meth)acryloyloxypropyl group, and a4-(meth)acryloyloxybutyl group are preferred. A methyl group, an ethylgroup, a propyl group, and an isopropyl group are more preferred. Inaddition, the substituents represented by the R₁ to the R₄ may beidentical to or different from one another. However, it is preferredthat the R₁ and the R₂ represent the same substituent, and the R₃ andthe R₄ represent the same substituent in consideration of the ease ofsynthesis of each of the compounds and the ease with which the compoundrepresented by the general formula (2) is incorporated at 1.0 mass % ormore and 10.0 mass % or less into the compound represented by thegeneral formula (1). In addition, in order that a production cost forthe optical composition may be reduced, it is desired that the R₁ andthe R₂ represent the same substituent, and the R₃ and the R₄ representthe same substituent, and any such substituent is specifically a methylgroup, an ethyl group, a propyl group, or an isopropyl group. Inconsideration of the dispersion characteristic and secondary dispersioncharacteristic of a cured product obtained by polymerizing thecomposition, the substituents represented by the R₁ to the R₄ are eachmore preferably a methyl group or an isopropyl group. When the molecularweights of the substituents represented by the R₁ to the R₄ are close to170, the dispersion characteristic and secondary dispersioncharacteristic of the cured product of the optical compositioncontaining the compound represented by the general formula (1) and thecompound represented by the general formula (2) reduce, and hence aneffect exhibited when the cured product is used as an optical elementreduces. Accordingly, the purity of the optical composition ispreferably increased to as high a value as possible. A recrystallizationmethod is desirably used as a method of increasing the purity becausethe amount of a residual solvent and the like in the compounds can bereduced.

In the compound represented by the general formula (1) and the compoundrepresented by the general formula (2), substituents represented by Z₁,Z₄, and Z₆ are each a structure represented by the general formula (3).In addition, substituents represented by Z₂, Z₃, Z₅, and Z₇ are notparticularly limited as long as the substituents are each a hydrogenatom, or a substituent bonded to a benzene ring through a carbon atom,an oxygen atom, a sulfur atom, or a nitrogen atom. However, when themolecular weights of the substituents increase, the dispersioncharacteristic and secondary dispersion characteristic of the opticalcomposition of the present invention reduce. Accordingly, the molecularweights are preferably less than 200. Specific examples of thesubstituents represented by the Z₂, the Z₃, the Z₅, and the Z₇ mayinclude, but not limited to, a hydrogen atom, a methyl group, an ethylgroup, an isopropyl group, a chloromethyl group, a dichloromethyl group,a trichloromethyl group, a fluoromethyl group, a difluoromethyl group, atrifluoromethyl group, a methoxy group, an ethoxy group, an isopropoxygroup, a chloromethyloxy group, a dichloromethyloxy group, atrichloromethyloxy group, a fluoromethyloxy group, a difluoromethyloxygroup, a trifluoromethyloxy group, a methylthio group, an ethylthiogroup, a propylthio group, a dimethylamino group, a diethylamino group,a dipropylamino group, a 2-(meth)acryloyloxyethoxy group, a3-(meth)acryloyloxypropoxy group, a 4-(meth)acryloyloxybutoxy group, anda structure represented by the general formula (3). In consideration ofthe transmittance of the cured product and prevention of the yellowingthereof in a reliability test, and the ease of synthesis of each of thecompounds, the substituents represented by the Z₂, the Z₃, the Z₅, andthe Z₇ are each preferably selected from the group consisting of ahydrogen atom, a methyl group, an ethyl group, an isopropyl group, amethoxy group, an ethoxy group, an isopropoxy group, a methylthio group,an ethylthio group, a propylthio group, a 2-(meth)acryloyloxyethoxygroup, a 3-(meth)acryloyloxypropoxy group, a 4-(meth)acryloyloxybutoxygroup, and a structure represented by the general formula (3). Infurther consideration of the ease of synthesis, the substituentsrepresented by the Z₂, the Z₃, the Z₅, and the Z₇ are each morepreferably selected from the group consisting of a hydrogen atom, amethyl group, an ethyl group, an isopropyl group, a methoxy group, anethoxy group, an isopropoxy group, a methylthio group, an ethylthiogroup, a propylthio group, and a structure represented by the generalformula (3). In consideration of the ease of synthesis, the ease ofavailability of raw materials for the optical composition to be used,and the production cost, the substituents represented by the Z₂, the Z₃,the Z₅, and the Z₇ are each preferably one selected from the groupconsisting of a hydrogen atom, a methyl group, an ethyl group, and anisopropyl group. Further, the Z₂, the Z₃, the Z₅, and the Z₇ each morepreferably represent a hydrogen atom. When the molecular weights of thesubstituents represented by the Z₂, the Z₃, the Z₅, and the Z₇ are closeto 200, the dispersion characteristic and secondary dispersioncharacteristic of the cured product of the optical compositioncontaining the compound represented by the general formula (1) and thecompound represented by the general formula (2) reduce, and hence theeffect exhibited when the cured product is used as an optical elementreduces. Accordingly, the purity of the optical composition ispreferably increased to as high a value as possible. Therecrystallization method is desirably used as a method of increasing thepurity because the amount of the residual solvent and the like in thecompounds can be reduced.

In a structure represented by the general formula (3), m is notparticularly limited as long as the molecular weights of the Z's do notexceed 200. However, the m represents 0 or 1 in consideration of theease of synthesis and the ease with which the compound represented bythe general formula (2) is incorporated at 1.0 mass % or more and 10.0mass % or less into the compound represented by the general formula (1),and the m preferably represents 0 in consideration of the ease ofsynthesis. In the structure represented by the general formula (3), Wrepresents a hydrogen atom or a methyl group, and V is not particularlylimited as long as the molecular weights of the Z's do not exceed 200.However, in consideration of the ease of synthesis, the ease with whichthe compound represented by the general formula (2) is incorporated at1.0 mass % or more and 10.0 mass % or less into the compound representedby the general formula (1), and the ease with which the purity isincreased, the V is selected from the group consisting of the followinggroups:

*—O—**; *—S—**;

*—O—C_(n)H_(2n)—O—**;*—S—C_(n)H_(2n)—O—**;—O—C_(n)H_(2n)—S—**; and*—S—C_(n)H_(2n)—S—**.

In the groups, * represents a bonding hand with an alkylene moiety,represents a bonding hand with a (meth)acryloyl group, and n representsone integer selected from the group consisting of 2 to 5. In a structurerepresented by C_(n)H_(2n) in the V, a substituent, such as a halogenatom, an alkyl group, an aromatic group, or a reactive functional group,may be present on a carbon atom. In consideration of the ease ofsynthesis, and the dispersion characteristic and secondary dispersioncharacteristic of the cured product, the V preferably represents any oneof the following structures:

*—O—**; *—S—*;

*—O—CH₂CH₂—O—**;*—O—CH₂CH₂CH₂—O—**;*—O—CH₂CH₂CH₂CH₂—O—**;*—O—CH₂CH₂CH₂CH₂CH₂—O—**;*—O—CH₂C(CH₃)₂CH₂—O—**;*—O—CH₂CH(CH₃)CH₂—O—**;*—O—CH(CH₃)CH₂CH(CH₃)—O—**;*—O—C(CH₃)₂CH₂CH₂—O—**;*—O—CH₂CH₂C(CH₃)₂—O—**;*—S—CH₂CH₂—O—**;*—S—CH₂CH₂CH₂—O—**;*—S—CH₂CH₂CH₂CH₂—O—**;*—S—CH₂CH₂CH₂CH₂CH₂—O—**;*—S—CH₂C(CH₃)₂CH₂—O—**;*—S—CH₂CH(CH₃)CH₂—O—**;*—S—CH(CH₃)CH₂CH (CH₃)—O—**;*—S—C(CH₃)₂CH₂CH₂—O—**;*—S—CH₂CH₂C(CH₃)₂—O—**;*—O—CH₂CH₂—S—**;*—O—CH₂CH₂CH₂—S—**;*—O—CH₂CH₂CH₂CH₂—S—**;*—O—CH₂CH₂CH₂CH₂CH₂—S—**;*—O—CH₂C(CH₃)₂CH₂—S—**;*—O—CH₂CH(CH₃)CH₂—S—**;*—O—CH(CH₃)CH₂CH(CH₃)—S—**;*—O—C(CH₃)₂CH₂CH₂—S—**;*—O—CH₂CH₂C(CH₃)₂—S—**;*—S—CH₂CH₂—S—**;*—S—CH₂CH₂CH₂—S—**;*—S—CH₂CH₂CH₂CH₂—S—**;*—S—CH₂CH₂CH₂CH₂CH₂—S—**;*—S—CH₂C(CH₃)₂CH₂—S—**;*—S—CH₂CH(CH₃)CH₂—S—**;*—S—CH(CH₃)CH₂CH(CH₃)—S—**;*—S—C(CH₃)₂CH₂CH₂—S—**; and*—S—CH₂CH₂C(CH₃)₂—S—.

In consideration of the ease of synthesis, the V more preferablyrepresents any one of the following structures:

*—O—**; *—S—**;

*—O—CH₂CH₂—O—**;*—O—CH₂CH₂CH₂—O—**;*—O—CH₂CH₂CH₂CH₂—O—**;*—O—CH₂CH₂CH₂CH₂CH₂—O—**;*—O—CH₂C(CH₃)₂CH₂—O—**;*—O—CH₂CH(CH₃)CH₂—O—**;*—O—CH(CH₃)CH₂CH(CH₃)—O—**;*—S—CH₂CH₂—O—**;*—S—CH₂CH₂CH₂—O—**;*—S—CH₂CH₂CH₂CH₂—O—**;*—S—CH₂CH₂CH₂CH₂CH₂—O—**;*—S—CH₂C(CH₃)₂CH₂—O—**;*—S—CH₂CH(CH₃)CH₂—O—**;*—S—CH(CH₃)CH₂CH(CH₃)—O—**;*—O—CH₂CH₂—S—**;*—O—CH₂CH₂CH₂—S—**;*—O—CH₂CH₂CH₂CH₂—S—**;*—O—CH₂CH₂CH₂CH₂CH₂—S—**;*—O—CH₂C(CH₃)₂CH₂—S—**;*—O—CH₂CH(CH₃)CH₂—S—**;*—O—CH(CH₃)CH₂CH(CH₃)—S—**;*—S—CH₂CH₂—S—**;*—S—CH₂CH₂CH₂—S—**;*—S—CH₂CH₂CH₂CH₂—S—**;*—S—CH₂CH₂CH₂CH₂CH₂—S—**;*—S—CH₂C(CH₃)₂CH₂—S—**;*—S—CH₂CH(CH₃)CH₂—S—**; and*—S—CH(CH₃)CH₂CH(CH₃)—S—**.

In consideration of the ease of synthesis of each of the compoundrepresented by the general formula (1) and the compound represented bythe general formula (2), in particular, the ease with which each of thecompounds is purified, the V preferably represents any one of thefollowing structures:

*—O—**; *—S—**;

—O—CH₂CH₂—O—**;*—O—CH₂CH₂CH₂—O—**;*—O—CH₂CH₂CH₂CH₂—O—**;*—O—CH₂CH₂CH₂CH₂CH₂—O—**;*—O—CH₂C(CH₃)₂CH₂—O—**;*—O—CH₂CH(CH₃)CH₂—O—**;*—O—CH(CH₃)CH₂CH(CH₃)—O—**;*—S—CH₂CH₂—S—**;*—S—CH₂CH₂CH₂—S—**;*—S—CH₂CH₂CH₂CH₂—S—**;*—S—CH₂CH₂CH₂CH₂CH₂—S—**;*—S—CH₂C(CH₃)₂CH₂—S—**;*—S—CH₂CH(CH₃)CH₂—S—**; and*—S—CH(CH₃)CH₂CH(CH₃)—S—**.

In consideration of, for example, the production cost, the odor of areagent, and the storage stability of each of the compounds, the V morepreferably represents any one of the following structures:

*—O—**; *—S—**;

*—O—CH₂CH₂—O—**;*—O—CH₂CH₂CH₂—O—**;*—O—CH₂CH₂CH₂CH₂—O—**;*—O—CH₂CH₂CH₂CH₂CH₂—O—**;*—O—CH₂C(CH₃)₂CH₂—O—**;*—S—CH₂CH₂—S—**;*—S—CH₂CH₂CH₂—S—**;*—S—CH₂CH₂CH₂CH₂—S—**; and*—S—CH₂C(CH₃)₂CH₂—S—**.

Although Z₈ is not particularly limited as long as the Z₈ represents astructure that can achieve the effects of the present invention, inconsideration of the ease of synthesis, the Z₈ desirably represents astructure represented by the V in a structure represented by the generalformula (3). In this case, however, the Z₈ does not represent *—O—** and*—S—**, and both of * and ** each represent a bonding hand with analkylene moiety. Further, the Z₈ preferably represents the samestructure as that represented by the V in the structure represented bythe general formula (3) of the Z₆ in consideration of the ease ofsynthesis and the ease with which the compound represented by thegeneral formula (2) is incorporated into the optical composition at 1.0mass % or more and 10.0 mass % or less with respect to the compoundrepresented by the general formula (1). Still further, it is morepreferred that in the compound represented by the general formula (1)and the compound represented by the general formula (2), structuresrepresented by the V's in the structures each represented by the generalformula (3), the structures serving as the Z₁, the Z₄, and the Z₆, andthe structure represented by the Z₈ be identical to one another in orderthat the effects of the optical composition of the present invention maybe exhibited.

Next, an effect of incorporating the compound represented by the generalformula (2) into the compound represented by the general formula (1) inthe optical composition of the present invention is described. Ingeneral, a polymerization inhibitor for suppressing the polymerizationof a polymerizable material is added to an optical composition stored ina storage bottle. However, when the polymerizable material crystallizes,the polymerization inhibitor cannot be present near a molecule of thepolymerizable material in a crystalline state, and hence thepolymerizable material is more liable to polymerize. Meanwhile, unlikepolymerization in a liquid state, polymerization in the crystallinestate is polymerization in a crystal unit, and hence there is a low riskof the polymerization of the contents in the entirety of the storagebottle. A polymer obtained by the polymerization of the crystal of thepolymerizable material has a low solubility in the optical composition,and hence deteriorates a scattering ratio in the cured product obtainedby polymerizing the optical composition. In addition, the polymer servesas one factor for a reduction in quality of the optical compositionbecause the polymer is identified as foreign matter.

In addition, when the crystallization of the polymerizable materialadvances in an optical composition in the state of a mixture havingadded thereto various additives, a nonuniform portion in which thepolymerization inhibitor and the additives concentrate occurs in theoptical composition to serve as one factor for the reduction in qualityof the optical composition. The occurrence of the nonuniform portionbecomes a problem in terms of process management because the occurrencerequires an additional step, such as re-stirring.

Meanwhile, a typical method of suppressing the crystallization of thepolymerizable material is, for example, a method involving adding amaterial having a high dissolving power, or a method involving adding amolecule that hardly crystallizes, the molecule having a molecularstructure similar to that of a molecule of the polymerizable materialwhose crystallization is to be suppressed, to inhibit the orientation ofthe molecule of the polymerizable material that advances at the time ofthe crystallization. In the former method, the material having a highdissolving power needs to be added in a large amount for obtaining theeffect. In the method, changes in optical characteristics of the curedproduct obtained by curing the optical composition may become problems,though the crystallization of the polymerizable material can besuppressed. In the latter method, as disclosed in Japanese PatentApplication Laid-Open No. 2014-198814, a method involving adding amolecule that more hardly crystallizes, the molecule having a molecularstructure similar to that of the molecule of the polymerizable materialwhose crystallization is to be suppressed, is general. The molecule thatmore hardly crystallizes, the molecule having the similar molecularstructure, is specifically, for example, a molecule obtained by theaddition of a flexible substituent having a long carbon chain to themolecular skeleton of the polymerizable material serving as a base or achange of a substituent of the material into a substituent having acarbon chain longer than the molecule whose crystallization is to besuppressed.

However, concern is raised in that the dispersion characteristic andsecondary dispersion characteristic of an optical composition containinga compound having a structure similar to that of the polymerizablematerial, the compound being obtained by performing the addition of theflexible substituent or the change into the substituent having thelonger carbon chain, reduce. Accordingly, in the present invention, thecompound represented by the general formula (2) having crystallinityhigher than that of the compound represented by the general formula (1)is incorporated into the compound represented by the general formula(1). With regard to the content of the compound represented by thegeneral formula (2), when the content is excessively small, acrystallization-suppressing effect is small, and when the content isexcessively large, the crystallization of the compound represented bythe general formula (2) is accelerated. Accordingly, the content of thecompound represented by the general formula (2) in the opticalcomposition of the present invention is preferably 1.0 mass % or moreand 10.0 mass % or less with respect to the compound represented by thegeneral formula (1). This case is desired because thecrystallization-suppressing effect of the compound represented by thegeneral formula (1) becomes suitable and the crystallization of thecompound represented by the general formula (2) can be suppressed. Thecontent is more preferably 3.0 mass % or more and 8.0 mass % or less.This case is desired because the crystallization-suppressing effect ofthe compound represented by the general formula (1) becomes moresuitable and the crystallization of the compound represented by thegeneral formula (2) can be suppressed to a larger extent, and hence thecrystallization-suppressing effect is expressed in a wide temperaturerange.

Next, a method of producing the compound represented by the generalformula (1) is described by way of an example. A production route forthe compound represented by the general formula (1) is not particularlylimited, and any production method can be adopted; provided that theproduction method includes at least the following synthesis steps (a),(b), and (c):

(a) a step of forming an aromatic ring (benzene ring)-aromatic ringbond;(b) an etherification (thioetherification) step; and(c) a step of introducing a (meth)acryloyl group.

In consideration of, for example, the ease of synthesis, the synthesissteps are performed in the following order: the step (a), the step (b),and the step (c).

In the step (a), a bond-forming reaction can be appropriately changed inaccordance with the kind of functional group that an aromatic ring has.Examples thereof include a coupling reaction based on a transition metalcatalyst, an oxidative coupling reaction between halides, and asubstitution reaction on an aromatic ring. In consideration of the yieldof the reaction, the coupling reaction based on the transition metalcatalyst is desired.

The coupling reaction based on the transition metal catalyst can beselected in accordance with the kind of functional group that anaromatic ring has. A typical method therefor is, for example, the Suzukicoupling involving utilizing boric acid or the like, the Stille couplinginvolving utilizing an organotin, or the Negishi coupling involvingutilizing an organozinc.

A typical method for an etherification reaction in the step (b) is, forexample, a Williamson ether synthesis method involving turning a hydroxygroup into a salt with sodium hydride, potassium hydroxide, or the like,and then adding a corresponding halide. Meanwhile, a thioetherificationreaction is performed in two steps, i.e., a thiol group-producingreaction, and a reaction between a thiol group and a halide. Here, thethiol group-producing reaction is achieved by, for example, transforminga hydroxy group into a substituent having activity for a nucleophilicsubstitution reaction (e.g., TsO—, Cl—, or CF₃S(═O)₂—O—), and thenperforming a nucleophilic substitution reaction involving using asulfide ion (S²⁻). In addition, in the reaction between the thiol groupand the halide, the above-mentioned Williamson ether synthesis method orthe like can be applied. In each of the etherification reaction and thethioetherification reaction, water management needs to be strictlyperformed because when moisture is included in a reaction condition, aside reaction advances to produce an alcohol form or a thiol form as aby-product.

In the step (c), a typical method for the introduction of a(meth)acryloyl group is, for example, a method involving esterifying ahydroxy group with a (meth)acrylic acid halide or (meth)acrylicanhydride, an ester exchange method involving using a lower alcoholester of (meth)acrylic acid, a method involving performingesterification between a hydroxy group and (meth)acrylic acid throughthe use of a dehydration condensation agent, such asN,N′-dicyclohexylcarbodiimide, or a method involving heating(meth)acrylic acid in the presence of a dehydrating agent, such assulfuric acid, to esterify a hydroxy group.

In addition, a polymerization inhibitor may be used as required so thatthe polymerization of the compound represented by the general formula(1) may not advance at the time of a reaction for the production of thecompound, at the time of its purification, or at the time of itsstorage. Examples of the polymerization inhibitor include:hydroquinones, such as p-benzoquinone, hydroquinone, hydroquinonemonomethyl ether, hydroquinone monoethyl ether, hydroquinone monopropylether, hydroquinone monobutyl ether, hydroquinone monopentyl ether,hydroquinone monohexyl ether, hydroquinone monooctyl ether, hydroquinonemonoheptyl ether, and 2,5-diphenyl-p-benzoquinone; N-oxy radicals, suchas tetramethylpiperidinyl-N-oxy radical (TEMPO); substituted catechols,such as tert-butylcatechol; amines, such as phenothiazine,diphenylamine, and phenyl-β-naphthylamine; nitrosobenzene; picric acid;molecular oxygen; sulfur; and copper(II) chloride. Of those,hydroquinones, phenothiazine, and N-oxyradicals are preferred from theviewpoints of a general-purpose property and the suppression of thepolymerization.

A lower limit for the usage amount of the polymerization inhibitor istypically 10 ppm or more, preferably 50 ppm or more with respect to thecompound represented by the general formula (1), and an upper limittherefor is typically 10,000 ppm or less, preferably 5,000 ppm or lesswith respect thereto. In the case where the usage amount of thepolymerization inhibitor is excessively small, i.e., less than 10 ppm,the following risk arises: the effect of the polymerization inhibitor isnot expressed or the effect is small, and hence the polymerizationadvances at the time of the reaction or at the time of condensation in aposttreatment step. In addition, the case where the usage amount of thepolymerization inhibitor is more than 10,000 ppm is not preferredbecause the following risk arises: the polymerization inhibitor servesas, for example, an impurity at the time of the production of a curedproduct to be described later, and has an adverse effect, such as theinhibition of the polymerization reactivity of the compound.

Meanwhile, with regard to a method of producing the compound representedby the general formula (2) in the present invention, as in the compoundrepresented by the general formula (1), a production route therefor isnot particularly limited, and its production is performed by the samemethod as the method of producing the compound represented by thegeneral formula (1); provided that the equivalent and addition time of areagent to be used need to be changed in order that the basic skeletonof the compound represented by the general formula (2) may be obtainedin the etherification (thioetherification) reaction of the step (b). Inaddition, a diol compound serving as a precursor of the compoundrepresented by the general formula (2) may be synthesized as a mixturewith a diol compound serving as a precursor of the compound representedby the general formula (1). Its content can be identified by, forexample, NMR or liquid chromatography. When the content of the diolcompound serving as the precursor of the compound represented by thegeneral formula (2) in the mixture is from 1.0 mass % to 10.0 mass %with respect to the diol compound serving as the precursor of thecompound represented by the general formula (1), the optical compositionof the present invention can be obtained by subjecting the precursors inthe mixture to the introduction of a (meth)acryloyl group of the step(c) to be described later. In addition, the optical composition of thepresent invention may be obtained by purifying and isolating the diolcompound serving as the precursor of the compound represented by thegeneral formula (2), then performing a (meth)acrylation reaction, andmixing the resultant with the compound represented by the generalformula (1). The diol compound serving as the precursor of the compoundrepresented by the general formula (1) and the diol compound serving asthe precursor of the compound represented by the general formula (2) canbe separately produced by adjusting the usage amount of a diol or adithiol to be used in the etherification reaction or thioetherificationreaction of the step (b).

Next, a cured product of the present invention is described.

A cured product of the present invention is a cured product, which isobtained by polymerizing the optical composition of the presentinvention, the cured product containing at least a structure representedby the general formula (4) and a structure represented by the generalformula (5), in which a content of the structure represented by thegeneral formula (5) in the cured product is 0.01 or more and 0.10 orless in terms of a substance amount ratio with respect to the structurerepresented by the general formula (4).

In the general formula (4) and the general formula (5), X₁, X₂, Y₁, andY₂, R₁ to R₄, and Z₁ to Z₈ are defined in the same manner as in the X₁,the X₂, the Y₁, and the Y₂, the R₁ to the R₄, and the Z₁ to the Z₈ inthe general formula (1) and the general formula (2) described above.Here, when the R₁ to the R₄ each represent an allyl group, a2-(meth)acryloyloxyethyl group, a 3-(meth)acryloyloxypropyl group, or a4-(meth)acryloyloxybutyl group, the R₁ to the R₄ in the general formula(4) and the general formula (5) may each represent a group in which adouble bond of an allyl group, a 2-(meth)acryloyloxyethyl group, a3-(meth)acryloyloxypropyl group, or a 4-(meth)acryloyloxybutyl group iscleaved to be bonded to another structure represented by the generalformula (4) or another structure represented by the general formula (5)through the broken line. In addition, the Z₁, the Z₄, and the Z₆ in thegeneral formula (4) and the general formula (5) may each represent agroup in which a double bond of the structure represented by the generalformula (3) is cleaved to be bonded to another structure represented bythe general formula (4) or another structure represented by the generalformula (5) through the broken line. Further, when the Z₂, the Z₃, theZ₅, and the Z₇ each represent a 2-(meth)acryloyloxyethoxy group, a3-(meth)acryloyloxypropoxy group, a 4-(meth)acryloyloxybutoxy group, orthe structure represented by the general formula (3) , the Z₂, the Z₃,the Z₅, and the Z₇ in the general formula (4) and the general formula(5) may each represent a group in which a double bond of the2-(meth)acryloyloxyethoxy group, the 3-(meth)acryloyloxypropoxy group,the 4-(meth)acryloyloxybutoxy group, or the structure represented by thegeneral formula (3) is cleaved to be bonded to another structurerepresented by the general formula (4) or another structure representedby the general formula (5) through the broken line. In addition, atleast two broken lines in the general formula (4) or the general formula(5) each represent a bond.

That is, the cured product of the present invention is a cured productobtained by polymerizing an optical composition containing at least acompound represented by the general formula (1) and a compoundrepresented by the general formula (2), in which a content of thecompound represented by the general formula (2) in the opticalcomposition is from 1.0 mass % to 10.0 mass % with respect to thecompound represented by the general formula (1).

In addition, a method of producing a cured product of the presentinvention is a method of producing a cured product, including: preparingan optical composition containing at least a compound represented by thegeneral formula (1) and a compound represented by the general formula(2), in which a content of the compound represented by the generalformula (2) in the optical composition is 1.0 mass % or more and 10.0mass % or less with respect to the compound represented by the generalformula (1); and polymerizing the optical composition to cure thecomposition:

in the general formula (1) and the general formula (2):

X₁, X₂, Y₁, and Y₂ each represent O or S, and may be identical to ordifferent from one another;

R₁ to R₄ each represent one selected from the group consisting of amethyl group, an ethyl group, a propyl group, an isopropyl group, anallyl group, a 2-(meth)acryloyloxyethyl group, a3-(meth)acryloyloxypropyl group, and a 4-(meth)acryloyloxybutyl group,and may be identical to or different from one another;

Z₁, Z₄, and Z₆ may each represent a structure represented by the generalformula (3);

Z₂, Z₃, Z₅, and Z₇ each represent one selected from the group consistingof a hydrogen atom, a methyl group, an ethyl group, an isopropyl group,a methoxy group, an ethoxy group, an isopropoxy group, a methylthiogroup, an ethylthio group, a propylthio group, a2-(meth)acryloyloxyethoxy group, a 3-(meth)acryloyloxypropoxy group, a4-(meth)acryloyloxybutoxy group, and a structure represented by thegeneral formula (3), and may be identical to or different from oneanother; and

Z₈ represents V in a structure represented by the general formula (3);

in the general formula (3), m represents 0 or 1, W represents a hydrogenatom or a methyl group, and V is selected from the group consisting ofthe following structures:

*—O—**; *—S—**;

*—O—C_(n)H_(2n)—O—**;*—S—C_(n)H_(2n)—O—**;*—O—C_(n)H_(2n)—S—**; and*—S—C_(n)H_(2n)—S—**;in each of the Z₁ to the Z₇, * of the structure represents a bondinghand with an alkylene moiety and ** of the structure represents abonding hand with a (meth)acryloyl group, in the Z₈, the V does notrepresent *—O—** and *—S—**, and both of * and ** each represent abonding hand with an alkylene moiety, and a structure represented byC_(n)H_(2n) in the V may have a substituent on a carbon atom, and nrepresents an integer selected from the group consisting of 2 to 5.

The cured product of the present invention is roughly classified intothe following aspects (A) to (D):

(A) a cured product obtained by polymerizing the compound represented bythe general formula (1) and the compound represented by the generalformula (2);(B) a cured product obtained by copolymerizing the compound representedby the general formula (1) and the compound represented by the generalformula (2), and the other polymerizable material capable ofcopolymerizing with the compounds;(C) a cured product obtained by dispersing the compound represented bythe general formula (1) and the compound represented by the generalformula (2) into the other polymerizable material capable ofcopolymerizing with the compounds, and copolymerizing the compounds andthe material; and(D) a cured product obtained by dispersing the compound represented bythe general formula (1) and the compound represented by the generalformula (2) into the other matrix polymer, and copolymerizing thecompounds.

When the cured product of the present invention is the cured product ofthe aspect (A), the cured product is produced by polymerizing an opticalcomposition containing the compound represented by the general formula(1) and the compound represented by the general formula (2), and apolymerization initiator. A polymerization inhibitor, a photosensitizer,a light stabilizer, a heat stabilizer, an antioxidant, a release agent,an antifungal agent, or the like may be further incorporated into theoptical composition as required.

Examples of the polymerization initiator include, but not limited to, apolymerization initiator that generates an active species, such as aradical species or a cation species, through light irradiation, and apolymerization initiator that generates an active species, such as aradical species, with heat.

Examples of the polymerization initiator that generates a radicalspecies through light irradiation include, but not limited to,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone,1-hydroxycyclohexyl phenyl ketone,2-hydroxy-2-methyl-1-phenyl-propan-1-one,bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 4-phenylbenzophenone,4-phenoxybenzophenone, 4,4′-diphenylbenzophenone, and4,4′-diphenoxybenzophenone.

In addition, suitable examples of the polymerization initiator thatgenerates a cation species through light irradiation include, but notlimited to, polymerization initiators such as iodonium(4-methylphenyl)[4-(2-methylpropyl)phenyl]-hexafluorophosphate.

Further, examples of the polymerization initiator that generates aradical species with heat include, but not limited to: azo compounds,such as azobisisobutylnitrile (AIBN); peroxides, such as benzoylperoxide, tert-butyl peroxypivalate, tert-butyl peroxyneohexanoate,1,1-dimethylbutyl peroxyneohexanoate, tert-butyl peroxyneodecanoate,1,1-dimethylbutyl peroxyneodecanoate, cumyl peroxyneohexanoate, andcumyl peroxyneodecanoate.

The addition amount of the polymerization initiator to be incorporatedinto the optical composition for producing the cured product of thisaspect preferably falls within the range of from 0.01 mass % or more to10.00 mass % or less with respect to the total mass of the compoundrepresented by the general formula (1) and the compound represented bythe general formula (2). The polymerization initiators may be used aloneor in combination thereof. The addition ratio of the polymerizationinitiator with respect to the compound represented by the generalformula (1) and the compound represented by the general formula (2) maybe appropriately selected in accordance with a light irradiation amountand an additional heating temperature. In addition, the addition ratiomay be adjusted in accordance with the target average molecular weightof a polymer to be obtained.

Examples of the polymerization inhibitor include, but not limited to:hydroquinone monoalkyl ether-based polymerization inhibitors, such ashydroquinone monomethyl ether, hydroquinone monoethyl ether,hydroquinone monopropyl ether, hydroquinone monobutyl ether,hydroquinone monopentyl ether, hydroquinone monohexyl ether,hydroquinone monooctyl ether, and hydroquinone monoheptyl ether; andphenol-based polymerization inhibitors each having a substituent, suchas 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. However,hydroquinone- and benzoquinone-based polymerization inhibitors are notsuitable because the polymerization inhibitors may be yellowed by UVirradiation.

Examples of the polymerization inhibitor include, but not limited to,the above-mentioned examples of the polymerization inhibitor at the timeof the reaction or at the time of the storage. The addition amount ofthe polymerization inhibitor preferably falls within the range of from0.01 mass % or more to 1.00 mass % or less with respect to the opticalcomposition. In addition, the polymerization initiators may be usedalone or in combination thereof. In consideration of a low degree ofcoloring of the composition, specifically, hydroquinone monoalkylether-based polymerization inhibitors are preferably utilized incombination.

Examples of the photosensitizer include, but not limited to,benzophenone, 4,4-diethylaminobenzophenone, 1-hydroxycyclohexyl phenylketone, isoamyl p-dimethylaminobenzoate, methyl 4-dimethylaminobenzoate,benzoin, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropylether, 2,2-diethoxyacetophenone, methyl o-benzoylbenzoate,2-hydroxy-2-methyl-1-phenylpropan-1-one, and acylphosphine oxides.

The light stabilizer is not particularly limited as long as the lightstabilizer does not have a large influence on the opticalcharacteristics of the cured product, and examples thereof include:benzotriazole-based compounds, such as2-(2H-benzotriazol-2-yl)-p-cresol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol,2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol,2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol,2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol,2,2′-methylenebis[6-(2H-benzotriazol-2-yl)]-4-(1,1,3,3-tetramethylbutyl)phenol,and 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol;cyanoacrylate-based compounds, such as ethyl2-cyano-3,3-diphenylacrylate and 2-ethylhexyl2-cyano-3,3-diphenylacrylate; triazine-based compounds; andbenzophenone-based compounds, such as octabenzone and2,2′-4,4′-tetrahydrobenzophenone. The light stabilizer may also serve asthe photosensitizer, and in that case, the photosensitizer may not beadded.

The heat stabilizer is not particularly limited as long as the heatstabilizer does not have a large influence on the opticalcharacteristics of the cured product, and examples thereof include:pentaerythritoltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate,octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, or alkylesters of 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acidwhose alkyl group has a side chain and consists of 7 to 9 carbon atoms;hindered phenol-based compounds, such as4,6-bis(octylthiomethyl)-o-cresol, 4,6-bis(dodecylthiomethyl)-o-cresol,ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)]propionate,and hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate;phosphorus-based compounds, such astris(2,4-di-tert-butylphenyl)phosphite; and sulfur-based compounds, suchas dioctadecyl-3,3′-thiodipropionate.

The antioxidant is not particularly limited as long as the antioxidantdoes not have a large influence on the optical characteristics of thecured product, and examples thereof include hindered amine-basedcompounds, such as bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate andbis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate.

When the cured product of the present invention is the cured product ofthe aspect (B), the cured product is produced by polymerizing an opticalcomposition formed of the compound represented by the general formula(1) and the compound represented by the general formula (2), and thepolymerizable material capable of copolymerizing with the compounds. Thecontent of the compound represented by the general formula (1) and thecompound represented by the general formula (2) in the opticalcomposition is desirably 1.0 mass % or more and 99 mass % or less. Inorder to set the dispersion characteristic and secondary dispersioncharacteristic of the cured product to fall within an area useful foroptical design, the content of the compound represented by the generalformula (1) and the compound represented by the general formula (2) ispreferably 50 mass % or more and 99 mass % or less. A polymerizationinhibitor, a photosensitizer, a light stabilizer, a heat stabilizer, anantioxidant, a release agent, an antifungal agent, or the like may befurther incorporated into the optical composition as required.

An example of the polymerizable material capable of copolymerizing withthe compounds is, but not particularly limited to, a (meth)acrylicmonomer. Examples thereof include, but not limited to: (meth)acrylatecompounds, such as 1,3-adamantanediol dimethacrylate,1,3-adamantanedimethanol dimethacrylate, tricyclodecanedimethanoldiacrylate, pentaerythritol tetraacrylate, propoxylated neopentyl glycoldiacrylate, dipropylene glycol diacrylate, ethoxylated bisphenol Adimethacrylate, tris(2-hydroxyethyl) isocyanurate triacrylate,2-(2-ethoxyethoxy)ethyl acrylate, stearyl acrylate, tetrahydrofurfurylacrylate, 2-phenoxyethyl acrylate, isodecyl acrylate, isobornylacrylate, isobornyl methacrylate, 1,3-butylene glycol diacrylate,1,4-butanediol diacrylate, diethylene glycol diacrylate, 1,6-hexanedioldiacrylate, triethylene glycol diacrylate, tripropylene glycoldiacrylate, dipropylene glycol diacrylate, triethylene glycoldimethacrylate, ethylene glycol dimethacrylate, tetraethylene glycoldimethacrylate, 1,4-butanediol dimethacrylate, diethylene glycoldimethacrylate, 1,6-hexanediol dimethacrylate, tripropylene glycoldimethacrylate, dipropylene glycol dimethacrylate, trimethylol propanetrimethacrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene,9,9-bis[4-(2-methacryloyloxyethoxy)phenyl]fluorene,9,9-bis[4-(2-acryloyloxy)phenyl]fluorene,9,9-bis[4-(2-methacryloyloxy)phenyl]fluorene, benzyl acrylate, benzylmethacrylate, butoxyethyl acrylate, butoxymethyl methacrylate,cyclohexyl acrylate, cyclohexyl methacrylate, 2-hydroxyethyl acrylate,2-hydroxymethyl methacrylate, glycidyl acrylate, glycidyl methacrylate,phenoxyethyl acrylate, phenoxyethyl methacrylate, phenyl methacrylate,ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethyleneglycol diacrylate, diethylene glycol dimethacrylate, triethylene glycoldiacrylate, triethylene glycol dimethacrylate, tetraethylene glycoldiacrylate, tetraethylene glycol dimethacrylate, polyethylene glycoldiacrylate, polyethylene glycol dimethacrylate, neopentyl glycoldiacrylate, neopentyl glycol dimethacrylate, ethylene glycol bisglycidylacrylate, ethylene glycol bisglycidyl methacrylate, bisphenol Adiacrylate, bisphenol A dimethacrylate,2,2-bis(4-acryloxyethoxyphenyl)propane,2,2-bis(4-methacryloxyethoxyphenyl)propane,2,2-bis(4-acryloxydiethoxyphenyl)propane,2,2-bis(4-methacryloxydiethoxyphenyl)propane, bisphenol F diacrylate,bisphenol F dimethacrylate, 1,1-bis(4-acryloxyethoxyphenyl)methane,1,1-bis(4-methacryloxyethoxyphenyl)methane,1,1-bis(4-acryloxydiethoxyphenyl)methane,1,1-bis(4-methacryloxydiethoxyphenyl)methane,1,1-bis(4-acryloxyethoxyphenyl)sulfone,1,1-bis(4-methacryloxyethoxyphenyl)sulfone,1,1-bis(4-acryloxydiethoxyphenyl)sulfone,1,1-bis(4-methacryloxydiethoxyphenyl)sulfone, dimethylol tricyclodecanediacrylate, trimethylol propane triacrylate, trimethylolpropanetrimethacrylate, glycerol diacrylate, glycerol dimethacrylate,pentaerythritol triacrylate, pentaerythritol tetraacrylate,pentaerythritol tetramethacrylate, methyl thioacrylate, methylthiomethacrylate, phenyl thioacrylate, benzyl thiomethacrylate, xylylenedithiol diacrylate, xylylene dithiol dimethacrylate, mercaptoethylsulfide diacrylate, and mercaptoethyl sulfide dimethacrylate; allylcompounds, such as allyl glycidyl ether, diallyl phthalate, diallylterephthalate, diallyl isophthalate, diallyl carbonate, and diethyleneglycol bisallyl carbonate; vinyl compounds, such as styrene,chlorostyrene, methylstyrene, bromostyrene, dibromostyrene,divinylbenzene, and 3,9-divinylspirobi(m-dioxane); anddiisopropenylbenzene.

The addition amount of the polymerizable material capable ofcopolymerizing with the compounds preferably falls within the range offrom 0.10 mass % or more to 80.00 mass % or less with respect to themass of the optical composition. The addition amount is more preferably0.10 mass % or more and 30.00 mass % or less in consideration of thefact that the dispersion characteristic and secondary dispersioncharacteristic of the cured product fall within the area useful foroptical design.

The polymerization initiator described in the aspect (A) can be used asa polymerization initiator to be incorporated into the opticalcomposition for producing the cured product of this aspect. The additionamount of the polymerization initiator preferably falls within the rangeof from 0.01 mass % or more to 10.00 mass % or less with respect to thetotal mass of polymerizable components. The polymerization initiatorsmay be used alone or in combination thereof. The addition ratio of thepolymerization initiator may be appropriately selected in accordancewith a light irradiation amount and an additional heating temperature.In addition, the addition ratio may be adjusted in accordance with thetarget average molecular weight of a polymer to be obtained.

The polymerization inhibitor described in the aspect (A) can be used asthe polymerization inhibitor to be incorporated into the opticalcomposition for producing the cured product of this aspect. The additionamount of the polymerization inhibitor preferably falls within the rangeof from 0.01 mass % or more to 10.00 mass % or less with respect to theoptical composition.

When the polymerization is initiated by irradiation with UV light or thelike, a known photosensitizer or the like can be used. Thephotosensitizer described in the aspect (A) can be used as thephotosensitizer. The addition amount of the photosensitizer to beincorporated into the optical composition for producing the curedproduct of this aspect preferably falls within the range of from 0.01mass % or more to 10.00 mass % or less with respect to the opticalcomposition.

The light stabilizer described in the aspect (A) can be used as thelight stabilizer to be incorporated into the optical composition forproducing the cured product of this aspect. The addition amount of thelight stabilizer preferably falls within the range of from 0.01 mass %or more to 10.00 mass % or less with respect to the optical composition.

The heat stabilizer to be incorporated into the optical composition forproducing the cured product of this aspect is, for example, the heatstabilizer described in the aspect (A). The addition amount of the heatstabilizer preferably falls within the range of from 0.01 mass % or moreto 10.00 mass % or less with respect to the optical composition.

The antioxidant described in the aspect (A) can be used as theantioxidant to be incorporated into the optical composition forproducing the cured product of this aspect. The addition amount of theantioxidant preferably falls within the range of from 0.01 mass % ormore to 10.00 mass % or less with respect to the optical composition.

When the cured product of the present invention is the cured product ofthe aspect (C), the cured product is produced by polymerizing an opticalcomposition obtained by dispersing the compound represented by thegeneral formula (1) and the compound represented by the general formula(2) into the polymerizable material capable of copolymerizing with thecompounds. The content of the polymerizable material capable ofcopolymerizing with the compounds to be incorporated into the opticalcomposition is desirably 1.0 mass % or more and 99.0 mass % or less. Thecontent of the compound represented by the general formula (1) and thecompound represented by the general formula (2) is preferably 1.0 mass %or more and 50.0 mass % or less in consideration of the dispersioncharacteristic and secondary dispersion characteristic of the curedproduct to be obtained, and compatibility between each of the compoundrepresented by the general formula (1) and the compound represented bythe general formula (2), and the polymerizable material.

A polymerization inhibitor, a photosensitizer, a light stabilizer, aheat stabilizer, an antioxidant, a release agent, an antifungal agent,or the like may be further incorporated into the optical composition asrequired.

The polymerizable material is not particularly limited as long as thedispersion characteristic and secondary dispersion characteristic of thecured product fall within an area useful for optical design.Specifically, for example, a (meth)acrylic monomer, an allyl compound, avinyl compound, a diisopropenylbenzene compound, an epoxy compound, or athiirane compound described in the aspect (B) can be used as thepolymerizable material in this aspect, but the polymerizable material isnot limited thereto.

The polymerization initiator described in the aspect (A) can be used asa polymerization initiator to be incorporated into the opticalcomposition for producing the cured product of this aspect. The additionamount of the polymerization initiator preferably falls within the rangeof from 0.01 mass % or more to 10.00 mass % or less with respect to thetotal mass of polymerizable components. The polymerization initiatorsmay be used alone or in combination thereof. The addition ratio of thepolymerization initiator may be appropriately selected in accordancewith a light irradiation amount and an additional heating temperature.In addition, the addition ratio may be adjusted in accordance with thetarget average molecular weight of a polymer to be obtained.

The polymerization inhibitor described in the aspect (A) can be used asthe polymerization inhibitor to be incorporated into the opticalcomposition of this aspect. The addition amount of the polymerizationinhibitor preferably falls within the range of from 0.01 mass % or moreto 10.00 mass % or less with respect to the optical composition.

When the polymerization is initiated by irradiation with UV light or thelike, a known photosensitizer or the like can be used. Thephotosensitizer described in the aspect (A) can be used as a typicalphotosensitizer. The addition amount of the photosensitizer to beincorporated into the optical composition for producing the curedproduct of this aspect preferably falls within the range of from 0.01mass % or more to 10.00 mass % or less with respect to the opticalcomposition.

The light stabilizer described in the aspect (A) can be used as thelight stabilizer to be incorporated into the optical composition forproducing the cured product of this aspect. The addition amount of thelight stabilizer preferably falls within the range of from 0.01 mass %or more to 10.00 mass % or less with respect to the optical composition.

The heat stabilizer described in the aspect (A) can be used as the heatstabilizer to be incorporated into the optical composition for producingthe cured product of this aspect. The addition amount of the heatstabilizer preferably falls within the range of from 0.01 mass % or moreto 10.00 mass % or less with respect to the optical composition.

The antioxidant described in the aspect (A) can be used as theantioxidant to be incorporated into the optical composition forproducing the cured product of this aspect. The addition amount of theantioxidant preferably falls within the range of from 0.01 mass % ormore to 10.00 mass % or less with respect to the optical composition.

When the cured product of the present invention is the cured product ofthe aspect (D), the cured product is produced by polymerizing an opticalcomposition formed of the compound represented by the general formula(1) and the compound represented by the general formula (2), and thematrix polymer capable of copolymerizing with the compound representedby the general formula (1) and the compound represented by the generalformula (2). The content of the matrix polymer compound to beincorporated into the optical composition is desirably 1.0 mass % ormore and 99.0 mass % or less. The content of the matrix polymer ispreferably 1.0 mass % or more and 50.0 mass % or less in considerationof the dispersion characteristic and secondary dispersion characteristicof the cured product to be obtained, and compatibility between each ofthe compound represented by the general formula (1) and the compoundrepresented by the general formula (2), and the matrix polymer. Apolymerization inhibitor, a photosensitizer, a light stabilizer, a heatstabilizer, an antioxidant, a release agent, an antifungal agent, or thelike may be further incorporated into the optical composition asrequired.

Examples of the matrix polymer include, but not limited to:(meth)acrylic polymers; allyl-based polymers; polyolefin-based resins,such as an ethylene homopolymer, a random or block copolymer of ethyleneand one or two or more kinds of α-olefins, such as and propylene,1-butene, 1-pentene, 1-hexene, and 4-methyl-l-pentene, a random or blockcopolymer of ethylene and one or two or more kinds of vinyl acetate,acrylic acid, methacrylic acid, methyl acrylate, and methylmethacrylate, a propylene homopolymer, a random or block copolymer ofpropylene and one or two or more kinds of α-olefins except propylene,such as 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene, a1-butene homopolymer, an ionomer resin, and a mixture of those polymers;hydrocarbon-based resins, such as a petroleum resin and a terpene resin;polyester-based resins, such as polyethylene terephthalate, polybutyleneterephthalate, and polyethylene naphthalate; polyamide-based resins,such as nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 6/66,nylon 66/610, and nylon MXD; acrylic resins, such as polymethylmethacrylate; styrene- or acrylonitrile-based resins, such aspolystyrene, a styrene-acrylonitrile copolymer, astyrene-acrylonitrile-butadiene copolymer, and polyacrylonitrile;polyvinyl alcohol-based resins, such as polyvinyl alcohol and anethylene-vinyl alcohol copolymer; polycarbonate resins; polyketoneresins; polymethylene oxide resins; polysulfone resins; polyimideresins; and polyamide imide resins. Those resins may be used alone or asa mixture thereof. In addition, any such matrix polymer is appropriatelyselected in consideration of the compatibility with each of the compoundrepresented by the general formula (1) and the compound represented bythe general formula (2), and the dispersion characteristic and secondarydispersion characteristic of the cured product.

The polymerization initiator described in the aspect (A) can be used asa polymerization initiator to be incorporated into the opticalcomposition for producing the cured product of this aspect. The additionamount of the polymerization initiator preferably falls within the rangeof from 0.01 mass % or more to 10.00 mass % or less with respect to thetotal mass of polymerizable components. The polymerization initiatorsmay be used alone or in combination thereof. The addition ratio of thepolymerization initiator may be appropriately selected in accordancewith a light irradiation amount and an additional heating temperature.In addition, the addition ratio may be adjusted in accordance with thetarget average molecular weight of a polymer to be obtained.

The polymerization inhibitor described in the aspect (A) can be used asthe polymerization inhibitor to be incorporated into the opticalcomposition for producing the cured product of this aspect. The additionamount of the polymerization inhibitor preferably falls within the rangeof from 0.01 mass % or more to 10.00 mass % or less with respect to theoptical composition.

When the polymerization is initiated by irradiation with UV light or thelike, a known photosensitizer or the like can be used. Thephotosensitizer described in the aspect (A) can be used as a typicalphotosensitizer. The addition amount of the photosensitizer to beincorporated into the optical composition for producing the curedproduct of this aspect preferably falls within the range of from 0.01mass % or more to 10.00 mass % or less with respect to the opticalcomposition.

The light stabilizer described in the aspect (A) can be used as thelight stabilizer to be incorporated into the optical composition forproducing the cured product of this aspect. The addition amount of thelight stabilizer preferably falls within the range of from 0.01 mass %or more to 10.00 mass % or less with respect to the optical composition.

The heat stabilizer described in the aspect (A) can be used as the heatstabilizer to be incorporated into the optical composition for producingthe cured product of this aspect. The addition amount of the heatstabilizer preferably falls within the range of from 0.01 mass % or moreto 10.00 mass % or less with respect to the optical composition.

The antioxidant described in the aspect (A) can be used as theantioxidant to be incorporated into the optical composition forproducing the cured product of this aspect. The addition amount of theantioxidant preferably falls within the range of from 0.01 mass % ormore to 10.00 mass % or less with respect to the optical composition.

A method of mixing the various additives, the general-purpose monomers,and the matrix polymer is not particularly limited as long as thematerials can be uniformly mixed, and examples thereof include: a methodinvolving mixing all the materials in a solvent or the like, and thenremoving the solvent; and a method involving heating the materials tomelt the materials, and mixing the molten materials as they are. Themethod involving mixing the materials in the solvent is preferred at thetime of the preparation of the optical composition for obtaining thecured product of the aspect (A), (B), or (C) because the mixture becomesuniform. Meanwhile, the method involving heating the materials andmixing the materials as they are is preferred at the time of thepreparation of the optical composition for obtaining the cured productof the aspect (D) in consideration of a low solubility of the matrixpolymer in a solvent.

The method involving removing the solvent is not particularly limited aslong as the amount of the solvent remaining in the optical compositionis small, and examples thereof include a vacuum distillation removalmethod and a distillation method. In the vacuum distillation removalmethod, the solvent is desirably removed by distillation under reducedpressure while a gas containing oxygen is flowed because thepolymerization reaction may be accelerated under reduced pressure. Inaddition, in the distillation method, it is desired that thepolymerization inhibitor be added or the heating temperature beappropriately adjusted because the polymerization reaction may beaccelerated by heating.

When the optical composition of the present invention is polymerized toproduce the cured product of any one of the aspects (A) to (D), thepolymerization reaction is initiated by the polymerization initiator inthe optical composition. When the polymerization initiator is aphotopolymerization initiator that generates an active species throughlight irradiation, the cured product of the present invention isproduced by irradiating the composition with light having a suitablewavelength with which the photopolymerization initiator generates anactive species. The light having the suitable wavelength is, forexample, UV light or visible light. In addition, when the polymerizationinitiator is a thermal polymerization initiator that generates an activespecies through heating, the cured product of the present invention isproduced by heating the composition to a suitable temperature at whichthe thermal polymerization initiator generates an active species. Thesuitable temperature is, for example, 80° C. or more and 180° C. orless.

Next, an optical element of the present invention and a method ofproducing the element are described with reference to the drawings.

The optical element of the present invention has a feature of beingobtained by molding the cured product of any one of the aspects (A) to(D). FIG. 2A and FIG. 2B are each a schematic view for illustrating anoptical lens serving as an example of the optical element of the presentinvention. In an optical element of FIG. 2A, a thin film (optical member10) obtained by molding and processing the cured product of the presentinvention is arranged on one surface of a lens substrate 20 serving as abase material. A method of producing the optical element of FIG. 2A is,for example, a method involving forming the cured product of the presentinvention of a layer structure having a small thickness on the basematerial formed of a light-transmitting material. Specifically, a moldformed of a metal material or the like is arranged so as to have acertain distance from a glass substrate, and a gap present between themold and the glass substrate is filled with the optical composition ofthe present invention that is fluid. After that, molding is performed bylightly pressing down the mold. Then, the optical composition ispolymerized while the mold is pressed down. The polymerization reactionis performed by light irradiation or heating.

When the polymerization of the optical composition is performed byphotopolymerization, for example, raw materials for the opticalcomposition, such as the monomers, subjected to the molding areuniformly irradiated with light through the light-transmitting materialto be utilized as the substrate, specifically the glass substrate. Thequantity of the irradiation light is appropriately selected inaccordance with a reaction mechanism involving utilizing aphotopolymerization initiator and with the content of thephotopolymerization initiator to be incorporated.

In such production of the cured product of the optical composition by aphotopolymerization reaction as described in the foregoing, it ispreferred that the entirety of the raw materials, such as the monomers,subjected to the molding be uniformly irradiated with the irradiationlight. Therefore, it is more preferred to select light having such awavelength that the light irradiation to be utilized can be uniformlyperformed through the light-transmitting material to be utilized as thesubstrate, such as the glass substrate. At this time, a reduction inthickness of the optical composition to be formed on the substrate ofthe light-transmitting material is more suitable for the presentinvention.

In addition, when the polymerization of the optical composition isperformed by thermal polymerization, the polymerization of the opticalcomposition may be performed by heating the mold, or the polymerizationof the optical composition may be performed by heating the opticalcomposition subjected to the molding in a heating apparatus, such as anoven. A heating temperature is appropriately selected in accordance witha reaction mechanism involving utilizing a thermal polymerizationinitiator and with the content of the thermal polymerization initiatorto be incorporated.

As in the production of the cured product of the optical composition bythe photopolymerization reaction, it is preferred that heat be uniformlyapplied to the entirety of the raw materials for the optical compositionsubjected to the molding. Therefore, a heating method to be utilizedmore preferably involves uniformly heating the optical compositionsubjected to the molding in the heating apparatus. In addition, when thethickness of the cured product to be formed on the mold is reduced, evenin a production method involving heating the mold to polymerize theoptical composition, the optical composition can be uniformly heated.

Meanwhile, in an optical element of FIG. 2B, the thin film (opticalmember 10) obtained by molding and processing the cured product of thepresent invention is arranged between two base materials, i.e., betweena lens substrate 30 and a lens substrate 40. A method of producing theoptical element of FIG. 2B is, for example, as described below. Theoptical composition of the present invention that is uncured and thelike are poured into a gap between the lens substrate 30 and the lenssubstrate 40, and molding is performed by lightly pressing down thecomposition and the like. Then, the cured product is obtained byperforming the photopolymerization of the uncured optical compositionwhile keeping the composition in the state. Thus, the optical element inwhich the cured product of the present invention is sandwiched betweenthe lens substrate 30 and the lens substrate 40 can be obtained.

In addition, the cured product can be formed by a thermal polymerizationmethod. In this case, it is desired that the temperature of the entiretyof the composition be further uniformized, and a reduction in thicknessof the cured product of the optical composition to be formed on thesubstrate of the light-transmitting material is more suitable for theoptical element of the present invention.

In addition, when the thickness of the cured product to be formed isincreased, the thickness of the cured product can be increased byappropriately selecting, for example, a light irradiation amount, alight irradiation intensity, and a light source taking the thickness,the absorption of light by a resin component, and the like intoconsideration, and a heating temperature and a heating time.

Meanwhile, when the cured product of the present invention is used asthe cured product of the aspect (C), a melt molding method can be usedas a method of molding the cured product. The use of the melt moldingmethod can provide a molded product excellent in characteristics, suchas low birefringence, mechanical strength, and dimensional accuracy.Examples of the melt molding method include press molding, extrusionmolding, and injection molding. Of those, injection molding is preferredfrom the viewpoints of moldability and productivity.

In addition, a molding condition in a molding step is appropriatelyselected in accordance with a purpose of use of the molded product orthe molding method. However, the temperature of the cured product in theinjection molding preferably falls within the range of from 150° C. to400° C., more preferably falls within the range of from 200° C. to 350°C., and particularly preferably falls within the range of from 200° C.to 330° C. When the cured product is molded in the temperature range,moderate flowability is imparted to the resin at the time of themolding, and hence the occurrence of a sink mark or strain in theoptical element of the present invention serving as the molded productcan be prevented. In addition, when the cured product is molded in thetemperature range, the occurrence of a silver streak due to the thermaldecomposition of the cured product can be prevented, and the yellowingof the optical element can be effectively prevented.

The optical element of the present invention can be utilized as anoptical lens, such as a camera lens. In addition, an optical apparatusof the present invention includes the optical element of the presentinvention and is, for example, a camera having the optical lens.

The present invention is described in more detail below by way ofExamples. The present invention is by no means limited to Examplesdescribed below without departing from the gist of the presentinvention. The molecular structure of a synthesized compound wasanalyzed with JNM-ECA400 NMR manufactured by JEOL Ltd. by dissolving 10mg of the synthesized compound in 1 ml of chloroform. In addition, thefollowing synthetic intermediate A and compound B were synthesized withreference to Japanese Patent Application Laid-Open No. 2014-43565, andthe following compound A was synthesized with reference to JapanesePatent Application Laid-Open No. 2012-167019.

With regard to the analysis of a compound represented by the generalformula (1) and a compound represented by the general formula (2), whenall of R₁ to R₄ are identical to one another, and all of Z₁ to Z₇ areidentical to one another, the analysis can be easily performed bycomparing the NMR shift positions of atoms in the R₁ and the R₂, and theNMR shift positions of atoms in the R₃ and the R₄ corresponding thereto.Alternatively, whether an analyzed compound is the compound representedby the general formula (1) or the compound represented by the generalformula (2) can be confirmed by confirming whether or not a(meth)acryloyl group is bonded to a structure represented by V throughthe analysis of the NMR shift position of the structure represented bythe V.

Synthesis Example 1 Synthesis of Compound C

A solution of 55% sodium hydride (5 g) in tetrahydrofuran (200 ml) wascooled to 0° C., and 1,2-ethanediol (5 g) was slowly dropped thereinto.Thus, a sodium salt of 1,2-ethanediol was prepared. The syntheticintermediate A (30 g) was gradually added to the prepared liquid at 0°C., and the temperature of the reaction liquid was increased to 25° C.Then, the reaction liquid was stirred as it was for 12 hours. A reactionend point was identified while the extent to which a reaction advancedwas observed by thin-layer chromatography (hereinafter “TLC”). Afterthat, a saturated aqueous solution of ammonium chloride (30 ml) wasgradually added to the reaction liquid to terminate the reaction. Acrystal was precipitated by pouring the reaction-terminated liquid intowater (300 ml), and the precipitated crystal was washed with water (100ml), methanol (100 ml), and hexane (100 ml) in this order. Thus, 38 g ofa synthetic intermediate B was obtained (yield: 72%).

Next, the synthetic intermediate B (38 g) was dissolved in ethyl acetate(100 ml). The solution was cooled to 10° C., and triethylamine (9 g) andmethacryloyl chloride (11 g) were dropped thereinto in this order. Afterthat, the mixture was stirred at the temperature for 6 hours while areaction state was monitored by TLC. After that, the mixture was dilutedwith toluene (300 ml). A 10% aqueous solution of sodium hydroxide (70ml) was added to the toluene-diluted liquid, and the mixture wasstirred. After that, the aqueous phase was separated and the remainingorganic phase was washed with water (100 ml) twice. The organic phasewas concentrated and then purified by silica gel column chromatography,and the resultant crude product was recrystallized from a mixed solventof ethyl acetate and hexane. Thus, 28 g of a compound C serving as awhite crystal was obtained (yield: 65%).

¹H-NMR (CDCl₃; TMS): δ1.45 (d, 6H), 3.32-4.04 (m, 12H), 3.86 (s, 6H),3.89 (s, 6H), 4.59-4.68 (m, 8H), 5.45-5.49 (m, 2H), 6.04-6.11 (m, 2H),6.92-6.97 (m, 4H), 7.14-7.20 (m, 4H), 7.22-7.28 (m, 4H), 7.57-7.69 (m,8H), 7.95-8.05 (m, 8H)

Synthesis Example 2 Synthesis of Compound D

A solution of 55% sodium hydride (5 g) in tetrahydrofuran (200 ml) wascooled to 0° C., and 1,4-butanedithiol (10 g) was slowly droppedthereinto. Thus, a sodium salt of 1,4-butanedithiol was prepared. Thesynthetic intermediate A (30 g) was gradually added to the preparedliquid at 0° C., and the temperature of the reaction liquid wasincreased to 25° C. Then, the reaction liquid was stirred as it was for12 hours. A reaction end point was identified while the extent to whicha reaction advanced was observed by TLC. After that, a saturated aqueoussolution of ammonium chloride (30 ml) was gradually added to thereaction liquid to terminate the reaction. A crystal was precipitated bypouring the reaction-terminated liquid into water (300 ml), and theprecipitated crystal was washed with water (100 ml), methanol (100 ml),and hexane (100 ml) in this order. Thus, 38 g of a syntheticintermediate C was obtained (yield: 61%).

Next, the synthetic intermediate C (38 g) was dissolved in ethyl acetate(100 ml). Then, the solution was cooled to 10° C., and triethylamine (9g) and methacryloyl chloride (11 g) were dropped thereinto in thisorder. After that, the mixture was stirred at the temperature for 6hours while a reaction state was monitored by TLC. After that, themixture was diluted with toluene (300 ml). A 10% aqueous solution ofsodium hydroxide (70 ml) was added to the toluene-diluted liquid, andthe mixture was stirred. After that, the aqueous phase was separated andthe remaining organic phase was washed with water (100 ml) twice. Theorganic phase was concentrated and then purified by silica gel columnchromatography, and the resultant crude product was recrystallized froma mixed solvent of ethyl acetate and hexane. Thus, 24 g of a compound Dserving as a white crystal was obtained (yield: 58%).

¹H-NMR (CDCl₃; TMS): δ1.44 (d, 6H), 1.48-1.95 (m, 12H), 2.43-2.87 (m,12H), 3.85 (s, 6H), 3.87 (s, 6H), 3.56-4.03 (m, 8H), 5.15-5.29 (m, 2H),5.89-6.03 (m, 2H), 6.90-6.95 (m, 4H), 7.08-7.16 (m, 4H), 7.20-7.28 (m,4H), 7.54-7.68 (m, 8H), 7.93-8.02 (m, 8H)

Synthesis Example 3 Synthesis of Compound E

A solution of 55% sodium hydride (5 g) in tetrahydrofuran (200 ml) wascooled to 0° C., and 1,4-butanedithiol (18 g) was slowly droppedthereinto. Thus, a sodium salt of 1,4-butanedithiol was prepared. Thesynthetic intermediate A (30 g) was gradually added to the preparedliquid, and the temperature of the reaction liquid was increased to 25°C. Then, the reaction liquid was stirred as it was for 12 hours. Areaction end point was identified while the extent to which a reactionadvanced was observed by TLC. After that, a saturated aqueous solutionof ammonium chloride (30 ml) was gradually added to the reaction liquidto terminate the reaction. A crystal was precipitated by pouring thereaction-terminated liquid into water (300 ml), and the precipitatedcrystal was washed with water (100 ml), methanol (100 ml), and hexane(100 ml) in this order. Thus, 28 g of a synthetic intermediate D wasobtained (yield: 82%).

Next, the synthetic intermediate D (28 g) was dissolved in ethyl acetate(100 ml). The solution was cooled to 10° C., and triethylamine (6 g) andmethacryloyl chloride (7 g) were dropped thereinto in this order. Afterthat, the mixture was stirred at the temperature for 6 hours while areaction state was monitored by TLC. After that, the mixture was dilutedwith toluene (300 ml). A 10% aqueous solution of sodium hydroxide (70ml) was added to the toluene-diluted liquid, and the mixture wasstirred. After that, the aqueous phase was separated and the remainingorganic phase was washed with water (100 ml) twice. The organic phasewas concentrated and then purified by silica gel column chromatography,and the resultant crude product was recrystallized from a mixed solventof ethyl acetate and hexane. Thus, 21 g of a compound E serving as awhite crystal was obtained (yield: 63%).

¹H-NMR (CDCl₃; TMS): δ1.43 (d, 6H), 1.54-1.86 (m, 8H), 2.43-2.68 (m,8H), 3.84 (s, 6H), 3.51-4.01 (m, 4H), 5.14-5.28 (m, 2H), 5.86-6.04 (m,2H), 6.88-6.94 (m, 2H), 7.03-7.15 (m, 2H), 7.16-7.27 (m, 2H), 7.53-7.68(m, 4H), 7.94-8.05 (m, 4H)

Synthesis Example 4 Synthesis of Compound F

The following compound F was synthesized with reference to synthesismethods disclosed in Japanese Patent Application Laid-Open No.2012-167019 and Japanese Patent Application Laid-Open No. 2014-43565while reagents were changed.

Diphenylsulfone-4,4′-diylbis(trifluoromethanesulfonate) (28 g)synthesized with reference to Japanese Patent Application Laid-Open No.2012-167019, 3-formyl-4-isopropyloxyphenylboronic acid (27 g), sodiumhydrogen carbonate (30 g), tetrakis(triphenylphosphine)palladium (1.3g), 1,4-dioxane (500 ml), and water (250 ml) were mixed in a reactionvessel, and the mixture was stirred at a reaction temperature of 80° C.for 3 hours. Next, 250 ml of water was added to the resultant reactionsolution, and then the reaction solution was stirred at 80° C. for 1hour, followed by the filtration and recovery of the precipitatedcrystal (crude crystal). After that, the crude crystal was washed withethanol, and was then purified by recrystallization from a mixed solventof hexane and ethyl acetate. Thus, a synthetic intermediate E wasobtained as a pale gray crystal.

Next, the resultant crystal was dissolved in methanol (200 ml) andtetrahydrofuran (200 ml), and the reaction solution was cooled to 0° C.After that, sodium borohydride (12 g) was slowly added to the solution,and the mixture was stirred at the temperature for 3 hours. After areaction end point had been identified by TLC, a 2 N aqueous solution ofhydrochloric acid (50 ml) was slowly added to the mixture, and theresultant reaction solution was stirred at room temperature for 1 hour.The produced crystal was washed with an aqueous solution of sodiumhydrogen carbonate and water in this order, and was purified byrecrystallization from a mixed solvent of ethanol, ethyl acetate, andhexane. Thus, 27 g of a synthetic intermediate F was obtained (in 2steps, yield: 90%).

The synthetic intermediate F (27 g) was dissolved in dichloromethane(300 ml). A reaction vessel was cooled to 0° C. and phosphorustribromide (27 g) was slowly dropped into the solution. After the totalamount of phosphorus tribromide had been dropped, the reaction solutionwas stirred for 3 hours while its temperature was increased to 20° C.The reaction solution was poured into water (2 L) at 10° C. or less withstirring, and the reaction was terminated by stirring the mixture at itwas for 0.5 hour. Only the organic phase was separated from the mixedliquid containing the organic phase and the aqueous phase, and wasevaporated to dryness by removing the solvent with an evaporator. 100Milliliters of tetrahydrofuran was added to the dry product to dissolvethe product.

The solution was poured into a container containing 2 L of water withstirring. Thus, a crystal was precipitated. The precipitated crystal wasfiltered, and the filtrate was washed with water until the filtratebecame neutral. After that, the resultant crystal was washed withmethanol (100 ml). The resultant crystal was dried by air blowing for 24hours, and was then dried with warm air at 70° C. for 24 hours toprovide 29 g of a synthetic intermediate G (yield: 88%).

A solution of 55% sodium hydride (3 g) in tetrahydrofuran (150 ml) wascooled to 0° C., and 1,3-propanediol (7 g) was slowly dropped thereinto.Thus, a sodium salt of 1,4-butanedithiol was prepared. The syntheticintermediate G (20 g) was gradually added to the prepared liquid, andthe temperature of the reaction liquid was increased to 25° C. Then, thereaction liquid was stirred as it was for 12 hours. A reaction end pointwas identified while the extent to which a reaction advanced wasobserved by TLC. After that, a saturated aqueous solution of ammoniumchloride (30 ml) was gradually added to the reaction liquid to terminatethe reaction. A crystal was precipitated by pouring thereaction-terminated liquid into water (300 ml), and the precipitatedcrystal was washed with water (100 ml), methanol (100 ml), and hexane(100 ml) in this order. Thus, 17 g of a synthetic intermediate H wasobtained (yield: 88%).

Next, the synthetic intermediate H (15 g) was dissolved in ethyl acetate(70 ml). Then, the solution was cooled to 10° C., and triethylamine (6g) and methacryloyl chloride (7 g) were dropped thereinto in this order.After that, the mixture was stirred at the temperature for 6 hours whilea reaction state was monitored by TLC. After that, the mixture wasdiluted with toluene (200 ml). A 10% aqueous solution of sodiumhydroxide (30 ml) was added to the toluene-diluted liquid, and themixture was stirred. After that, the aqueous phase was separated and theremaining organic phase was washed with water (40 ml) twice. The organicphase was concentrated and then purified by silica gel columnchromatography, and the resultant crude product was recrystallized froma mixed solvent of ethyl acetate and hexane. Thus, 11 g of a compound Fserving as a white crystal was obtained (yield: 63%).

¹H-NMR (CDCl₃; TMS): δ1.52 (d, 12H), 1.73-1.92 (m, 4H), 1.98 (s, 6H),3.37-3.72 (m, 6H), 4.01 (t, 4H), 4.08-4.23 (m, 4H), 5.15-5.26 (m, 2H),5.84-6.03 (m, 2H), 6.85-6.91 (m, 2H), 7.05-7.19 (m, 2H), 7.19-7.28 (m,2H), 7.53-7.70 (m, 4H), 7.93-8.04 (m, 4H)

Synthesis Example 5 Synthesis of Compound G

The synthetic intermediate J (20 g) was dissolved in ethyl acetate (70ml). Then, the solution was cooled to 10° C., and triethylamine (12 g)and methacryloyl chloride (11 g) were dropped thereinto in this order.After that, the mixture was stirred at the temperature for 6 hours whilea reaction state was monitored by TLC. After that, the mixture wasdiluted with toluene (200 ml). A 10% aqueous solution of sodiumhydroxide (40 ml) was added to the toluene-diluted liquid, and themixture was stirred. After that, the aqueous phase was separated and theremaining organic phase was washed with water (50 ml) twice. The organicphase was concentrated and then purified by silica gel columnchromatography, and the resultant crude product was recrystallized froma mixed solvent of ethyl acetate and hexane. Thus, 15 g of a compound Gserving as a white crystal was obtained (yield: 58%).

¹H-NMR (CDCl₃; TMS): δ2.02 (s, 6H), 3.72 (s, 6H), 4.24 (s, 4H),5.17-5.28 (m, 2H), 5.90-6.05 (m, 2H), 6.86-6.90 (m, 2H), 7.04-7.17 (m,2H), 7.15-7.25 (m, 2H), 7.55-7.67 (m, 4H), 7.91-8.01 (m, 4H)

(Procedure for Production of Evaluation Sample)

(1) Preparation of Optical Composition

A compound represented by the general formula (1) and a compoundrepresented by the general formula (2) were weighed and mixed so thatthe contents of the respective materials became contents described inExamples or Comparative Examples. 0.2 Mass percent of 4-methoxyphenolserving as a polymerization inhibitor, 0.2 mass % of1-hydroxy-cyclohexyl phenyl ketone (IRGACURE 184/manufactured by BASF(former Ciba)) serving as a polymerization initiator, and 10 mass % ofan alkoxylated aliphatic diacrylate with respect to the mixture wereweighed, and all the materials were dissolved in acetone and mixed.After that, acetone was removed by distillation. Thus, an opticalcomposition was prepared.

Example 1

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 1.0 mass% of the compound C with respect to the compound A.

Example 2

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 5.0 mass% of the compound C with respect to the compound A.

Example 3

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 10.0 mass% of the compound C with respect to the compound A.

Example 4

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 5.0 mass% of the compound C with respect to the compound B.

Example 5

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 5.0 mass% of the compound D with respect to the compound E.

Example 6

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 5.0 mass% of the compound C with respect to the compound E.

Example 7

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 5.0 mass% of the compound C with respect to the compound F.

Example 8

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 5.0 mass% of the compound C with respect to the compound G.

Comparative Example 1

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 0.3 mass% of the compound C with respect to the compound A.

Comparative Example 2

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 11.0 mass% of the compound C with respect to the compound A.

Comparative Example 3

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 0.3 mass% of the compound C with respect to the compound B.

Comparative Example 4

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 0.3 mass% of the compound C with respect to the compound E.

Comparative Example 5

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 5.0 mass% of the compound B with respect to the compound A.

Comparative Example 6

An optical composition prepared in accordance with the procedure for theproduction of an evaluation sample, the composition containing 10.0 mass% of the compound C with respect to ethoxylated (2) bisphenol Adimethacrylate (comparative compound B).

(2) Production of Evaluation Sample

(2a) Sample for Refractive Index Measurement

Two disc-type glass substrates each having a diameter of 30 mm wereprepared, and the optical composition serving as a measuring object, thecomposition containing the polymerization inhibitor, the polymerizationinitiator, and the like, was sandwiched between the glass substrateshaving placed therebetween a spacer so as to have a uniform thickness of500 μm. The optical composition sandwiched between the two glasssubstrates was cured by irradiating the sample with UV light. Thus, asample for refractive index measurement was produced.

(2b) Sample for Confirmation of Crystallization

A brown bottle (10 ml) was filled with 5±1 g of the optical compositionof each of Examples and Comparative Examples serving as a measuringobject, and was left at rest in a thermostatic bath at 80° C. for 1hour. After that, the bottle was left at rest in a thermostatic bath at23° C.

(Method of evaluating Produced Sample)

(3) Measurement and Evaluation

(3a) Refractive Index, Dispersion Characteristic (Abbe Number), andSecondary Dispersion Characteristic (θg,F)

Measurement was performed with an Abbe refractometer (Kalnew OpticalIndustrial Co., Ltd.). A refractive index at a wavelength of 587.6 nm,and a dispersion characteristic and a secondary dispersioncharacteristic calculated from the following equations are shown in thetable.

Abbe number (dispersion characteristic): [ν_(d)]=(n _(d)−1)/(n _(F) −n_(C))

Secondary dispersion characteristic: [θg, F]=(n _(g) −n _(F))/(n _(F) −n_(C))

(3b) Confirmation of Crystallization

The sample for the confirmation of crystallization was left at rest inthe thermostatic bath at 23° C. for 24 hours, and was then removed fromthe thermostatic bath. Then, the sample for the confirmation ofcrystallization was irradiated with light from the outside of the brownbottle by using the LED light of SPA-10SD manufactured by HayashiWatch-Works Co., Ltd., and the presence or absence of the occurrence ofa crystal having a size that was able to be visually observed (crystalwhose longest side had a length of 2 mm or more) in the sample for theconfirmation of crystallization was confirmed. An example in which acrystal whose longest side had a length of 2 mm or more occurred wasevaluated as D, an example in which a crystal whose longest side had alength of 1 mm or more and less than 2 mm occurred was evaluated as C,an example in which a crystal whose longest side had a length of lessthan 1 mm occurred was evaluated as B, and an example in which nocrystal occurred was evaluated as A. The results are shown in the table.

The reasons why the time period for which the bottle was left at rest inthe thermostatic bath was set to 24 hours are as described below. Whenthe heated optical composition is directly stored in a refrigerator or afreezer, a harmful effect, such as the breakage of the container or thewarming of a substance that has already been stored, occurs. Therefore,the optical composition needs to be placed in the refrigerator or thefreezer after having been cooled to 23° C. over 24 hours. In addition,when a component in the optical composition crystallizes in the coolingstep, unevenness occurs in a cured product obtained by polymerizing theoptical composition.

TABLE 1 Refractive Abbe index number θ g, F Crystallization Example 11.602 21.1 0.72 A Example 2 1.602 21.1 0.72 A Example 3 1.602 21.1 0.72B Example 4 1.601 21.2 0.71 B Example 5 1.602 21.2 0.72 B Example 61.602 21.2 0.72 B Example 7 1.601 21.3 0.71 B Example 8 1.604 20.6 0.74B Comparative 1.602 21.1 0.72 D Example 1 Comparative 1.602 21.1 0.72 CExample 2 Comparative 1.601 21.2 0.71 C Example 3 Comparative 1.602 21.20.72 D Example 4 Comparative 1.602 21.0 0.72 D Example 5 Comparative1.598 22.3 0.69 A Example 6

The optical composition of the present invention can suppress theoccurrence of the unevenness of a cured product obtained by polymerizingthe optical composition due to crystallization because the compositioncan suppress the crystallization. Further, the cured product of thepresent invention obtained by polymerizing the optical composition ofthe present invention and the optical element of the present inventionobtained by molding the cured product each have the followingcharacteristics: the dispersion characteristic (Abbe number (ν_(d))) andsecondary dispersion characteristic (θg,F) of refractive indices arehigh (high θg,F characteristic), and a chromatic aberration-correctingfunction is high. Accordingly, the optical element can be utilized in anapparatus having a plurality of lenses, such as camera lenses.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2016-093263, filed May 6, 2016, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A cured product, comprising at least: a structurerepresented by the general formula (4); and a structure represented bythe general formula (5), wherein a content of the structure representedby the general formula (5) in the cured product is 0.01 or more and 0.10or less in terms of a substance amount ratio with respect to thestructure represented by the general formula (4):

in the general formula (4) and the general formula (5): X₁, X₂, Y₁, andY₂ each represent O or S, and may be identical to or different from oneanother; R₁ to R₄ each represent one selected from the group consistingof a methyl group, an ethyl group, a propyl group, an isopropyl group,an allyl group, a 2-(meth)acryloyloxyethyl group, a3-(meth)acryloyloxypropyl group, and a 4-(meth)acryloyloxybutyl group,and may be identical to or different from one another; when the R₁ tothe R₄ each represent an allyl group, a 2-(meth)acryloyloxyethyl group,a 3-(meth)acryloyloxypropyl group, or a 4-(meth)acryloyloxybutyl group,the R₁ to the R₄ may each represent a structure having a bond formedwith a cleaved double bond of the allyl group, the2-(meth)acryloyloxyethyl group, the 3-(meth)acryloyloxypropyl group, orthe 4-(meth)acryloyloxybutyl group; Z₁, Z₄, and Z₆ may each represent astructure represented by the general formula (3) or a structure having abond formed with a cleaved double bond of a structure represented by thegeneral formula (3); Z₂, Z₃, Z₅, and Z₇ each represent one selected fromthe group consisting of a hydrogen atom, a methyl group, an ethyl group,an isopropyl group, a methoxy group, an ethoxy group, an isopropoxygroup, a methylthio group, an ethylthio group, a propylthio group, a2-(meth)acryloyloxyethoxy group, a 3-(meth)acryloyloxypropoxy group, a4-(meth)acryloyloxybutoxy group, and a structure represented by thegeneral formula (3), and may be identical to or different from oneanother; when the Z₂, the Z₃, the Z₅, and the Z₇ each represent a2-(meth)acryloyloxyethoxy group, a 3-(meth)acryloyloxypropoxy group, a4-(meth)acryloyloxybutoxy group, or a structure represented by thegeneral formula (3), the Z₂, the Z₃, the Z₅, and the Z₇ may eachrepresent a structure having a bond formed with a cleaved double bond ofthe 2-(meth)acryloyloxyethoxy group, the 3-(meth)acryloyloxypropoxygroup, the 4-(meth)acryloyloxybutoxy group, or the structure representedby the general formula (3); at least two broken lines in the generalformula (4) or the general formula (5) each represent the bond formedwith the cleaved double bond; and Z₈ represents V in a structurerepresented by the general formula (3);

in the general formula (3), m represents 0 or 1, W represents a hydrogenatom or a methyl group, and V is selected from the group consisting ofthe following structures: *—O—**; *—S—**; *—O—C_(n)H_(2n)—O—**;*—S—C_(n)H_(2n)—O—**; *—O—C_(n)H_(2n)—S—**; and *—S—C_(n)H_(2n)—S—**; ineach of the Z₁ to the Z₇, * represents a bonding hand with an alkylenemoiety and ** represents a bonding hand with a (meth)acryloyl group, inthe Z₈, the V does not represent *—O—** and *—S—**, and both of * and **each represent a bonding hand with an alkylene moiety, and a structurerepresented by C_(n)H_(2n) in the V may have a substituent on a carbonatom, and n represents an integer selected from the group consisting of2 to
 5. 2. A cured product according to claim 1, wherein the structurerepresented by the general formula (4) and the structure represented bythe general formula (5) are copolymerized with another polymerizablematerial.
 3. A cured product according to claim 2, wherein the anotherpolymerizable material comprises a matrix polymer.
 4. A cured product,which is obtained by polymerizing an optical composition containing atleast a compound represented by the general formula (1) and a compoundrepresented by the general formula (2), wherein a content of thecompound represented by the general formula (2) in the opticalcomposition is 1.0 mass % or more and 10.0 mass % or less with respectto the compound represented by the general formula (1):

in the general formula (1) and the general formula (2): X₁, X₂, Y₁, andY₂ each represent O or S, and may be identical to or different from oneanother; R₁ to R₄ each represent one selected from the group consistingof a methyl group, an ethyl group, a propyl group, an isopropyl group,an allyl group, a 2-(meth)acryloyloxyethyl group, a3-(meth)acryloyloxypropyl group, and a 4-(meth)acryloyloxybutyl group,and may be identical to or different from one another; Z₁, Z₄, and Z₆each represent a structure represented by the general formula (3); Z₂,Z₃, Z₅, and Z₇ each represent one selected from the group consisting ofa hydrogen atom, a methyl group, an ethyl group, an isopropyl group, amethoxy group, an ethoxy group, an isopropoxy group, a methylthio group,an ethylthio group, a propylthio group, a 2-(meth)acryloyloxyethoxygroup, a 3-(meth)acryloyloxypropoxy group, a 4-(meth)acryloyloxybutoxygroup, and a structure represented by the general formula (3), and maybe identical to or different from one another; and Z₈ represents V in astructure represented by the general formula (3);

in the general formula (3), m represents 0 or 1, W represents a hydrogenatom or a methyl group, and V is selected from the group consisting ofthe following structures: *—O—**; *—S—**; *—O—C_(n)H_(2n)—O—**;*—S—C_(n)H_(2n)—O—**; *—O—C_(n)H_(2n)—S—**; and *—S—C_(n)H_(2n)—S—**; ineach of the Z₁ to the Z₇, * of the structure represents a bonding handwith an alkylene moiety and ** of the structure represents a bondinghand with a (meth)acryloyl group, in the Z₈, the V does not represent*—O—** and *—S—**, and both of * and ** each represent a bonding handwith an alkylene moiety, and a structure represented by C_(n)H_(2n) inthe V may have a substituent on a carbon atom, and n represents aninteger selected from the group consisting of 2 to
 5. 5. An opticalelement, which is obtained by molding a cured product containing atleast a structure represented by the general formula (4) and a structurerepresented by the general formula (5), wherein a content of thestructure represented by the general formula (5) in the cured product is0.01 or more and 0.10 or less in terms of a substance amount ratio withrespect to the structure represented by the general formula (4):

in the general formula (4) and the general formula (5): X₁, X₂, Y₁, andY₂ each represent O or S, and may be identical to or different from oneanother; R₁ to R₄ each represent one selected from the group consistingof a methyl group, an ethyl group, a propyl group, an isopropyl group,an allyl group, a 2-(meth)acryloyloxyethyl group, a3-(meth)acryloyloxypropyl group, and a 4-(meth)acryloyloxybutyl group,and may be identical to or different from one another; when the R₁ tothe R₄ each represent an allyl group, a 2-(meth)acryloyloxyethyl group,a 3-(meth)acryloyloxypropyl group, or a 4-(meth)acryloyloxybutyl group,the R₁ to the R₄ may each represent a structure having a bond formedwith a cleaved double bond of the allyl group, the2-(meth)acryloyloxyethyl group, the 3-(meth)acryloyloxypropyl group, orthe 4-(meth)acryloyloxybutyl group; Z₁, Z₄, and Z₆ may each represent astructure represented by the general formula (3) or a structure having abond formed with a cleaved double bond of a structure represented by thegeneral formula (3); Z₂, Z₃, Z₅, and Z₇ each represent one selected fromthe group consisting of a hydrogen atom, a methyl group, an ethyl group,an isopropyl group, a methoxy group, an ethoxy group, an isopropoxygroup, a methylthio group, an ethylthio group, a propylthio group, a2-(meth)acryloyloxyethoxy group, a 3-(meth)acryloyloxypropoxy group, a4-(meth)acryloyloxybutoxy group, and a structure represented by thegeneral formula (3), and may be identical to or different from oneanother; when the Z₂, the Z₃, the Z₅, and the Z₇ each represent a2-(meth)acryloyloxyethoxy group, a 3-(meth)acryloyloxypropoxy group, a4-(meth)acryloyloxybutoxy group, or a structure represented by thegeneral formula (3), the Z₂, the Z₃, the Z₅, and the Z₇ may eachrepresent a structure having a bond formed with a cleaved double bond ofthe 2-(meth)acryloyloxyethoxy group, the 3-(meth)acryloyloxypropoxygroup, the 4-(meth)acryloyloxybutoxy group, or the structure representedby the general formula (3); at least two broken lines in the generalformula (4) or the general formula (5) each represent the bond formedwith the cleaved double bond; and Z₈ represents V in a structurerepresented by the general formula (3);

in the general formula (3), m represents 0 or 1, W represents a hydrogenatom or a methyl group, and V is selected from the group consisting ofthe following structures: *—O—**; *—S—**; *—O—C_(n)H_(2n)—O—**;*—S—C_(n)H_(2n)—O—**; *—O—C_(n)H_(2n)—S—**; and *—S—C_(n)H_(2n)—S—**; ineach of the Z₁ to the Z₇, * represents a bonding hand with an alkylenemoiety and ** represents a bonding hand with a (meth)acryloyl group, inthe Z₈, the V does not represent *—O—** and *—S—**, and both of * and **each represent a bonding hand with an alkylene moiety, and a structurerepresented by C_(n)H_(2n) in the V may have a substituent on a carbonatom, and n represents an integer selected from the group consisting of2 to
 5. 6. An optical element according to claim 5, wherein the opticalelement comprises a lens.
 7. An optical element according to claim 5,wherein the optical element comprises one of an optical lens having thecured product arranged on a base material and an optical lens having thecured product arranged between two base materials.
 8. An opticalapparatus, comprising the optical element of claim
 5. 9. An opticalcomposition, comprising at least: a compound represented by the generalformula (1); and a compound represented by the general formula (2),wherein a content of the compound represented by the general formula (2)in the optical composition is 1.0 mass % or more and 10.0 mass % or lesswith respect to the compound represented by the general formula (1):

in the general formula (1) and the general formula (2): X₁, X₂, Y₁, andY₂ each represent O or S, and may be identical to or different from oneanother; R₁ to R₄ each represent one selected from the group consistingof a methyl group, an ethyl group, a propyl group, an isopropyl group,an allyl group, a 2-(meth)acryloyloxyethyl group, a3-(meth)acryloyloxypropyl group, and a 4-(meth)acryloyloxybutyl group,and may be identical to or different from one another; Z₁, Z₄, and Z₆each represent a structure represented by the general formula (3); Z₂,Z₃, Z₅, and Z₇ each represent one selected from the group consisting ofa hydrogen atom, a methyl group, an ethyl group, an isopropyl group, amethoxy group, an ethoxy group, an isopropoxy group, a methylthio group,an ethylthio group, a propylthio group, a 2-(meth)acryloyloxyethoxygroup, a 3-(meth)acryloyloxypropoxy group, a 4-(meth)acryloyloxybutoxygroup, and a structure represented by the general formula (3), and maybe identical to or different from one another; and Z₈ represents V in astructure represented by the general formula (3);

in the general formula (3), m represents 0 or 1, W represents a hydrogenatom or a methyl group, and V is selected from the group consisting ofthe following structures: *—O—**; *—S—**; *—O—C_(n)H_(2n)—O—**;*—S—C_(n)H_(2n)—O—**; *—O—C_(n)H_(2n)—S—**; and *—S—C_(n)H_(2n)—S—**; ineach of the Z₁ to the Z₇, * of the structure represents a bonding handwith an alkylene moiety and ** of the structure represents a bondinghand with a (meth)acryloyl group, in the Z₈, the V does not represent*—O—** and *—S—**, and both of * and ** each represent a bonding handwith an alkylene moiety, and a structure represented by C_(n)H_(2n) inthe V may have a substituent on a carbon atom, and n represents aninteger selected from the group consisting of 2 to
 5. 10. An opticalcomposition according to claim 9, wherein the X₁, the X₂, the Y₁, andthe Y₂ each represent O.
 11. An optical composition according to claim9, wherein: the R₁ to the R₄ each represent one selected from the groupconsisting of a methyl group, an ethyl group, a propyl group, and anisopropyl group; and the Z₂, the Z₃, the Z₅, and the Z₇ each representone selected from the group consisting of a hydrogen atom, a methylgroup, an ethyl group, and an isopropyl group.
 12. An opticalcomposition according to claim 9, wherein: the R₁ to the R₄ eachrepresent a methyl group or an isopropyl group; and the Z₂, the Z₃, theZ₅, and the Z₇ each represent a hydrogen atom.
 13. An opticalcomposition according to claim 9, wherein in the general formula (3),the m represents 0 and the V represents any one of the followingstructures: *—O—**; —S—**; *—O—CH₂CH₂—O—**; *—O—CH₂CH₂CH₂—O—**;*—O—CH₂CH₂CH₂CH₂—O—**; *—O—CH₂C(CH₃)₂CH₂—O—**; *—S—CH₂CH₂—S—**;*—S—CH₂CH₂CH₂—S—**; *—S—CH₂CH₂CH₂CH₂—S—**; and *—S—CH₂C(CH₃)₂CH₂—S—**;provided that in each of the Z₁ to the Z₇, * represents a bonding handwith an alkylene moiety and ** represents a bonding hand with a(meth)acryloyl group, and in the Z₈, the V does not represent *—O—** and*—S—**, and both of * and ** each represent a bonding hand with analkylene moiety.
 14. A method of producing a cured product, comprising:preparing an optical composition containing at least a compoundrepresented by the general formula (1) and a compound represented by thegeneral formula (2), a content of the compound represented by thegeneral formula (2) in the optical composition being 1.0 mass % or moreand 10.0 mass % or less with respect to the compound represented by thegeneral formula (1); and polymerizing the optical composition to curethe composition:

in the general formula (1) and the general formula (2): X₁, X₂, Y₁, andY₂ each represent O or S, and may be identical to or different from oneanother; R₁ to R₄ each represent one selected from the group consistingof a methyl group, an ethyl group, a propyl group, an isopropyl group,an allyl group, a 2-(meth)acryloyloxyethyl group, a3-(meth)acryloyloxypropyl group, and a 4-(meth)acryloyloxybutyl group,and may be identical to or different from one another; Z₁, Z₄, and Z₆each represent a structure represented by the general formula (3); Z₂,Z₃, Z₅, and Z₇ each represent one selected from the group consisting ofa hydrogen atom, a methyl group, an ethyl group, an isopropyl group, amethoxy group, an ethoxy group, an isopropoxy group, a methylthio group,an ethylthio group, a propylthio group, a 2-(meth)acryloyloxyethoxygroup, a 3-(meth)acryloyloxypropoxy group, a 4-(meth)acryloyloxybutoxygroup, and a structure represented by the general formula (3), and maybe identical to or different from one another; and Z₈ represents V in astructure represented by the general formula (3);

in the general formula (3), m represents 0 or 1, W represents a hydrogenatom or a methyl group, and V is selected from the group consisting ofthe following structures: *—O—**; —S—**; *—O—C_(n)H_(2n)—O—**;*—S—C_(n)H_(2n)—O—**; *—O—C_(n)H_(2n)—S—**; and *—S—C_(n)H_(2n)—S—**; ineach of the Z₁ to the Z₇, * of the structure represents a bonding handwith an alkylene moiety and ** thereof represents a bonding hand with a(meth)acryloyl group, in the Z₈, the V does not represent *—O—** and*—S—**, and both of * and ** each represent a bonding hand with analkylene moiety, and a structure represented by C_(n)H_(2n) in the V mayhave a substituent on a carbon atom, and n represents an integerselected from the group consisting of 2 to
 5. 15. A method of producinga cured product according to claim 14, wherein the optical compositionfurther contains a polymerizable material capable of copolymerizing withthe compound represented by the general formula (1) and the compoundrepresented by the general formula (2).
 16. A method of producing acured product according to claim 15, wherein the compound represented bythe general formula (1) and the compound represented by the generalformula (2) are dispersed into the polymerizable material capable ofcopolymerizing with the compounds.
 17. A method of producing a curedproduct according to claim 14, wherein the optical composition furthercontains a matrix polymer compound.